Adaptations result from interactions between organisms and their ______.
Natural selection is based on Darwin’s observation that individuals most likely to survive and reproduce are those ________.
with traits best suited to their current environment
The history of life on Earth is recorded in _______.
Which is an example of an acquired trait?
the ability to write
What is a fossil?
the remains of an ancient organism
The modern synthesis theory states that evolution occurs through changes in the gene pool of _______.
Darwin’s theory of common descent states that all organisms _______.
evolved from past organisms
According to the theory of _______, today’s organisms evolved from past organisms.
Which is an example of a population?
all the sugar maple trees in a state park
Reproductive separation may result in the _______ of two different species.
Which two ideas did Darwin use to explain evolution?
natural selection and common descent
When did Lamarck publish his ideas on evolution?
Over many generations, darker fur color becomes more common in a population of squirrels living in a shady area. This is an example of _______.
What is biological evolution?
changes in the gene pool of a population over time
Which idea did Lamarck propose that was rejected by his fellow scientists?
acquired traits can be passed to offspring
In 2003, what was achieved by the Human Genome Project?
The entire sequence of human DNA was identified
How did the separation of Earth’s continents affect biological evolution?
populations adapted to the new conditions of each region
What type of information is recorded in a trace fossil?
evidence of an organisms activities
What do paleontologists use to determine the actual age of rocks?
Which field of biology studies the structures of different species of animals?
Fossils on one continent may be similar to fossils on another continent. This observation supports which theory?
What is Earth’s crust?
the outermost layer on Earth’s surface
________ provide evidence of common ancestry among organisms.
similarities in DNA sequences
Which type of rock may contain fossils?
From earliest to most recent, what is the correct order in which organisms appear in the fossil record?
invertebrates, amphibians, dinosaurs, and mammals
What is genetic drift?
random changes in the gene pool of a small population
Which term describes the movement of alleles into and out of a population?
The Hardy-Weinberg principle states that ________ in a population do not change unless outside factors affect the gene pool.
Which process adds new genes to a gene pool?
When no living members of a species exist, the species _______.
has gone extinct
What is recombination?
new groupings of alleles in offspring
What is one reason that cheetahs are endangered?
Which population is subject to genetic drift?
a small population
The Hardy-Weinberg principle is written as the equation p^2+2pq+q^2 =1. What does the p represent?
the frequency of the dominant allele
Mutations are important for evolution because they _________.
are the source of new genetic variation
One consequence of genetic drift is _________.
loss of genetic variation
What can cause changes in DNA sequences?
Floods, droughts, fires, and earthquakes are examples of ________.
Recombination occurs during ________.
Which scenario causes gene flow?
an animal moves to a new population and mates
Which factor does not take a population out of Hardy-Weinberg equilibrium?
What is the effect of differential reproduction over time?
changes in a population’s gene pool
People can breed cats for specific traits such as coat color through _______?
A scientist uses artificial selection to produce a new type of cow. Compared to their parent, the new cows are _______?
the same species with different genetic makeup
What is required for a person to have sickle cell disease?
the person is homozygous for the trait
Which is not one of Darwin’s four main ideas of natural selection?
evolution always improves organisms
Which statement about natural selection is true?
environmental changes determine which animals survive
Darwin noticed that birds that were good at finding scarce food in the winter had a better chance of surviving and producing offspring. What did he call this struggle for existence?
What must be done for dogs to receive a particular trait?
mate two dogs that have the desired trait
Some individuals produce more offspring than others. Which term describes this observation?
How many African Americans are carrier of the sickle cell allele?
1 in 11
Which is not part of macroevolution?
Which process can be observed in the laboratory?
The change of England’s Biston betularia moth populations from light colored to dark colored is an example of _______.
What is macroevolution?
major changes in populations over a long time
What cause England’s Biston betularia moth populations to change over time from light colored to dark colored?
changes in allele frequencies
Which two factors work together to affect an organism’s phenotype?
genes and the environment
Which is part of microevolution?
What do scientists often use to study macroevolution?
the fossil record
Which evolutionary mechanism caused the increase in dark colored Biston betularia moths in England in the 1800s?
Which phenotypic change is genetic?
the flower color in a population changes over time
Why are horses and donkeys considered different species even though they can interbreed?
because their offspring (mules) are infertile
What factor can cause two populations to become reproductively isolated?
What is an organism’s niche?
it’s interactions with the living and nonliving parts of the environment
Which best describes the biological species concept?
species are populations that interbreed and produce fertile offspring
What type of speciation occurs when a plant population becomes reproductively isolated while living with its parent population?
Which key morphological feature is used to classify organisms as mammals?
What must occur for the gene pool within a population to change?
natural selection or genetic drift
Which two fields of study provide the core information that is used to classify organisms?
morphology and biochemistry
Which is one cause of speciation?
populations become reproductively isolated
How does sympatric speciation differ from allopatric speciation?
sympatric speciation involves a behavioral barrier, while allopatric speciation involves a physical barrier
In the 1930s, how did Dobzhansky and Mayr explain the origin of species?
species originate through allopatric speciation
A species is divided through geographic isolation. Over several generations, they lose the ability to interbreed. How are these two populations classified?
as two separate species
How are Dobzhansky and Mayr’s ideas about the origin of species similar to Darwin’s?
they thought the evolution of new species is linked to environmental changes
After speciation occurs, what happens to the species’ gene pools?
they become more and more different over time
According to the theory of punctuated equilibrium, when does stasis occur?
when environmental conditions are stable
What is the most likely explanation for how speciation occurs?
it occurs by more than one method
Paleontologists have found that after a major extinction occurs,
many new species often appear around the same time
According to the theory of punctuated equilibrium, which event could lead to speciation?
a meteor strikes Earth
Which best describes how long it usually takes for speciation to occur?
What is the theory of punctuated equilibrium?
it describes one way that new species arise
How does mass extinction affect species that survive?
they fill new roles in the changed environment
The mass extinctions that occurred 250 million years ago and 65 million years may have been due to gradual processes or ________.
a large comet or asteroid striking Earth
What is the main cause of extinction on Earth today?
human impact on the environment
How does the rate of extinction compare to the rate of species formation on Earth today?
the rate of extinction is faster
What is instantaneous speciation?
the formation of a new species over a few generations
A particular plant species is pollinated by a certain insect species. The insect species depends on the plant species for food. Which term describes how the relationship forms?
Which shows the correct order from smallest to largest?
species, population, community
How is a community different from a population?
a community is a group of many different species, while a population is made up of individuals of one particular species
What has occurred when large numbers of species die out over a short period of time?
Why are small populations more prone to genetic disease?
they have a greater frequency of harmful genes
Which taxonomic level for a given genus includes the greatest number of species?
What characteristic do all members of Eukarya have that members of Eubacteria do not have?
cells with nuclei
What is one way that members of Archaebacteria are different from members of Eubacteria?
they have different types of cell walls and cell membranes
What are the characteristics of Archaebacteria?
they are single cells that lack a nucleus and tend to live in extreme conditions
Which two groups are the most similar in physical characteristics?
archaea and eubacteria
Which belong in the domain Eukarya?
Which is a member of the domain Eubacteria?
The science of classifying organisms based on features they share is called ________.
Which is the correct interpretation of the scientific name Homo sapiens?
Homo is the genus and sapiens is the species
Which characteristics do scientists use to group species?
ancestors and DNA
How many words are there in the scientific name for a species using the Linnaeus classification system?
Which eubacteria help plants in the production of protiens?
Freezing food ______ the action of bacteria.
What term describes the whip-like structure that helps cells move through liquids?
Which is a class of extremophile?
What characteristic is used to group the three kinds of Eubacteria?
What is a chemosynthetic organism?
it uses sulfur or other elements as a source of energy
What are streptococci?
chains of spherical bacteria
Which would likely live near a crack in the deep ocean floor that spews scalding water?
Which would likely live in a bog, a sewage treatment plant, or a cow’s intestine?
Which would likely live in the Great Salt Lake?
Which kind of organism does not generally require oxygen or sunlight to live?
What is true of flagellates?
they can move through water
What is true of paramecia?
they are ciliates
What happens to a euglena when sunlight is not present?
it absorbs food from the environment
When would slime molds be likely to gather one form one, large structure?
when food and water are scarce
What kind of organism gets food using cilia?
How are protozoa similar to animals?
they can get food and move
Which type of algae is called seaweed and belongs to the division Phaeophyta
What is true of cilia?
they are like hairs
What characteristic do all protists have in common?
cell nuclei that contain DNA
What kind of protist causes dysentery?
Where are slime molds often found?
in damp soil or rotting material
What is a spore?
a reproductive cell produced by slime molds
Where are most algae found?
in freshwater and salt water
What food product is made using a fungus?
What do fungi have in common with plants?
their cells have nuclei that contain DNA
What kind of organism caused the Great Potato Famine in Ireland in the 1800s?
What are hyphae made of?
membranes and cytoplasm
Which part of a mushroom can you see above the ground?
Which statement correctly describes the function of each lichen part?
algae provide food, bacteria provide nitrogen, and fungi provide structure
What do fungi give off after they digest the food that they absorb?
carbon and nitrogen
How do hyphae spread from one area to another?
they grow quickly underground
What do fungi have in common with animals?
they are heterotrophs
How is penicillin used?
to kill bacteria that cause disease
Two different species belong to the same class. What other levels of classification do they have in common?
kingdom and phylum
What is the function of sori?
sori release haploid cells
Where are the spore containing sori of a fern found?
on the underside of a fern frond
What is the function of a moss’s rhizoid?
to obtain water
What vascular plant tissue is made of dead cells?
How are moss spores produced?
by sporophytes through meiosis
Where does xylem transport water?
from roots to leaves
Mycorrhiza form relationships between fungi and which part of vascular plants?
How are moss gametes produced?
by gamophytes through mitosis
What is the meaning of the term germinate?
to start growth
Where does fertilization take place in conifers?
in the ovary of a female cone
Which part of a flower contains the ovary?
Many flowers produce nectar. What is a purpose of nectar?
to attract birds and insects
What is another name for a flowering plant?
Which statement about male and female cones is true?
male cones are smaller than female cones
How many months of a year do most conifers have green leaves?
Gymnosperms were the first plants to reproduce using ________.
Which part of a flower will develop into fruit?
What does a seed contain?
a plant embryo and stored food
Which describes most woody stems?
What is one function of plant stems?
to transport water and food
Which structures are not found in simple leaves?
In which part of a root is vascular tissue found?
the inner layer
A plant that responds to touch is showing which of the following?
In gravotropism, in which direction to the roots grow?
In which part of a leaf is food made?
Which describes herbaceous stems?
A plant that grows toward light shows which of the following?
How mant growing seasons do plants with herbaceous stems usually survive?
What is one function of roots?
to take in minerals from the soil
Cnidarians such as jellyfish have radial symmetry. How are the body parts of cnidarians arranged?
like spokes on a wheel
How many cell layers are found in a blastula?
Which system controls the coordinated movement of animals?
How many copies of each chromosome are found in most animal cells?
Pinworms have small bodies, bilateral symmetry, and complete digestive tracts. What type of animal are they?
Which is true of all animals?
they are heterotrophs
How many copies of each chromosome are found in animal sex cells?
Which is a feature of a flatworm?
What is the name for an organized group of cells that wokr together?
Organisms that must eat food for energy are ________.
How many pairs of legs does an arachnid have?
What is found in all adult echinoderms?
What is one common function of an arthropods antennae?
How does an echinoderm use its tube feet?
Which is the largest group of arthropods?
Which insect goes through complete metamorphosis?
Where do echinoderms live?
in marine environments
Where do most crustaceans live?
Which arthropods have many body segments, with two pairs of legs on each segment?
Which is a feature of all arthropods?
Chordate embryos develop a notochord along the dorsal side. This position is located at the ________ of the embryo.
Which of the following is a feature of humans?
Where do amphibian larvae live?
Most of the species in the class _______ lay amniotic eggs.
Which animals are the oldest vertebrate fossils?
fish with no jaws
Which types of embryos have pharyngeal slits?
The class mammalia contains the only animals that _______.
have mammary glands
Which body parts do birds have?
feathers, beaks, and scales
How does a bony fish use the swim bladder?
to move up and down in water
Which animal is an ectotherm?
What process causes behavior patterns to change over generations as a result of reproductive success?
change through natural selection
What is a scientist called who observes animals in orfer to explain their behavior?
A peacock spreading its tail to attract a mate is sending an _________ stimilus?
What term describes anything that causes an organism to react?
What term describes the way an organism responds to a stimulus?
Which of the following is an example of a learned behavior?
birds returning to a backyard bird feeder
Mammals generally care for their young. Most turtles abandon their young. What term describes both of these behaviors?
Which is an external stimulus?
The way a particular species of bird constructs its nest is an example of ___________?
a fixed action pattern behavior
Animals with which kind of behavior are most adaptable to change?
An animal that hides under a rock to avoid predators is responding to a(n) _________ stimulus.
A mouse runs for cover in the presence of a cat. The cat is an example of a(n) ________ stimulus.
Which is not a characteristic of imprinting?
the mother must be present
A female mammal nursing her offspring is an example of what type of behavior?
Which is not a combination of innate and learned behavior?
Which best describes a prey animal?
one that is eaten by other animals
Which is a component of all innate behaviors?
Courtships belongs to what class of behaviors?
Warning coloration is an example of what kind of behavior?
A bird that perfects the sound and notes of its species song as it ages shows what type of learning?
What type of learning describes when animals learn by watching or listening others of their species?
Which best describes a predator animal?
one that eats other animals
Animals with territorial behaviors show _________.
What term describes the behaviors between males and females of the same species for the purposes of mating?
Viceroy butterflies are not poisonous, but they look just like the poisonous monarch butterflies. Which behavior does the viceroy use to deter birds that would otherwise eat it?
All wild birds of the same species sing the same song. How do the birds learn their species song?
by listening to it
When a male bird of paradise spreads its tail and does a dance to impress his potential mate, what signals is it using?
body display and movement
When an animal uses two kinds of signals together to obtain a response, there is a communication _________.
What term describes a chemical signal made in sweat glands?
Which is a characteristic of agonistic interaction?
Animals raising their young in packs is an example of ________.
A pheromone is a signal detected as a(n) _______.
What is it called when an organism signals another that their interaction is not serious or threatening?
What behavior is shown by two bighorn sheep butting heads in a fight for a female?
Why is the alarm calling of the vervet monkey an example of advanced communication?
the response is learned and varies over time
What type of behavior is characterized by the display of body parts or release of a scent for the purpose of attracting a mate?
In his experiment, Nicko Tinbergen determined that a female wasp can find its nest by using _____.
Which level of organization includes the most interactions?
Which describes the ability of a community to resist change?
Which is an example of commensalism?
barnacles benefit from living on whales, and they do not hurt the whales
Which term is a type of symbiosis?
The organisms in a community are interdependent. What does this mean?
the organisms rely on each other for survival
A symbiotic relationship in which two different organisms benefit from living together is called ________.
What is the largest level of organization for the environment?
Fleas and dogs are in a symbiotic relationship called __________.
What does population density measure?
the degree of crowding of a population
Barnacles live on whales. Whales carry the barnacles around, which helps the barnacles feed. The whales are unaffected. This is an example of ___________.
When the number of organisms increases in an ecosystem, the _________.
number of resources is usually the same
Which is a density-independent factor?
Which will probably decrease population density?
When grass is randomly distributed throughout an environment, a population of deer that eats grass is most likely to have a ________ pattern.
A period in which the densities of populations increase or decrease at the same time is called a _______.
Which tends to increase the size of a population?
Which increases as a population grows?
Which will probably increase population density?
increase in the food supply
Which distribution pattern describes pine trees on a pine tree farm?
What distribution pattern describes wolves that live in packs?
Which plants are usually the first to grow during secondary succession?
Secondary succession could occur after a __________.
disturbance has destroyed populations in a community
Which is true of secondary succession?
it occurs in land and marine communities
Primary succession can occur after a ___________.
volcanic eruption produces a new island
Succession is the process of __________ in a community.
Which plants are the first to grow during primary succession?
Where is primary succession likely to occur?
on a new rock created by a volcanic eruption
Ecological change in a community following a major disturbance is called _________.
Which activity could trigger primary succession?
a volcanic eruption
Which is true of primary succession?
it starts on nonliving rock and land
A community that experiences major changes undergoes _________.
Which are the first organisms to start the process of primary succession?
From where do chemotrophs get energy?
Mice eat corn. Hawks eat mice. Which term describes corn in this food chain?
Which is an example of a phototroph?
Mice eat corn. Hawks eat mice. Which term describes hawks in this food chain?
Mice eat corn. Hawks eat mice. What is the source of all the energy in this food chain?
Which term describes how a person gets energy?
Which one is a chemotroph?
a box turtle
A phototroph is to a chemotroph as __________.
a plant is to an animal
Which is at the bottom of an energy pyramid?
What is the direct source of energy for phototrophs?
What role do decomposers play in the nitrogen cycle?
they return nitrogen to the soil
How do plants get nitrogen?
by absorbing it from soil
Which nutrient do organisms tend to get from their local ecosystem?
Nutrients move through ecosystems in different ways. Which nutrient cycles through organisms, rivers, rain, and the atmosphere?
Which process changes carbon dioxide into organic molecules?
What is the name of the process of liquid water changing into water vapor due to heating?
Which is an example of precipitation?
What happens when solar energy heats a body of water?
Which kind of nutrients cycle through the atmosphere?
those that can exist as gases
Which process returns water to Earth?
Which factor controls the water cycle?
energy from the sun
Which process produces carbon dioxide?
Most of the nitrogen in the atmosphere is found in what form?
as nitrogen gas
Which biome is commonly found near the equator?
Which type of forest contains several kinds of cone-bearing trees and typically receives a lot of snow in winter?
Ecosystems that experience the same climate conditions are grouped together into larger regions called ________.
Which biome has no large trees because much of the soil is frozen?
What characteristic is used to divide aquatic biomes into three zones?
Which is true of the regions near the Earth’s equator?
they receive more solar energy than the poles
What is another name for the average weather conditions in a region over a long period of time?
Which type of forest contains many trees that shed their leaves during fall and winter?
Which biome contains both freshwater and saltwater?
Which biome typically experiences hot summers, cold winters, and lots of rain?
temperate deciduous forest
Dog excrement is carried by rain into bodies of water, where it causes algae to grow rapidly and crowd out other organisms in the ecosystem. What is this process called?
What may happen to a species whose limited habitat is destroyed by land developement?
it will become extinct
Ozone is a molecule in the upper atmosphere that is made up of three atoms of ___________.
Introduced species often take over an ecosystem because they usually __________.
have no competitors
What type of unhealthful air pollution occurs when ozone near the ground mixes with otehr polluting gases?
Approximately how many species become extinct on Earth each day?
What effect does human activity have on many ecosystems?
it destroys habitats
What process causes gases in the atmosphere to trap heat near the surface of Earth?
To help ecosystems thrive, humans must gain a better understanding of ________.
ecology and the environment
How many people are added to the world population each year?
Conservation biology uses ecological information to restore damaged _________.
What is not part of Earth’s biodiversity?
Which is an important source of carbon monoxide emissions that contributes to the greenhouse effect?
What term describes a species that has far fewer members today than in the past?
What term is used to describe the reuse of aluminum in old soda cans to make new products?
If a native species has been labeled as endangered, what is the appropriate response?
gather data to design a recovery plan
What form of waste cannot be recycled to make new products?
How can humans reduce the number of landfills?
produce less trash
What is the main reason that governments create natural areas called reserves?
to protect weakened ecosystems and their wildlife
What is a landfill?
a place where trash is collected
Science helps people learn about the way the world works. What is the goal of technology?
to make things that solve problems
Scientific and technological discoveries are accepted if their evidence can be _________.
What is the purpose of a patent?
to protect ownership of a new technology
Models and computer simulations are sometimes used to test the ___________ of a new technology.
What term is used for the study of nonliving parts of Earth?
To reduce the chances of system failure, engineers may use _____________.
Creating new things to solve problems and improve life depends on the close interaction of which two fields?
science and technology
What area of study applies scientific findings to create ways for solving problems or improving life?
Which is not a source of funding for scientific research?
What might engineers use to test a new software design?
Products that are created to solve problems in new ways result from advances in __________.
Where are the first reports of new scientific disciveries published?
What happens when the body releases perspiration?
water evaporates from the skin
The skin covering the human body consists of ____ layers.
Which system fights off disease?
Which part of the skin keeps in heat?
Which part of the skin contains blood vessels, nerves, and glands?
Which system moves the body?
The __________ system includes the heart.
The __________ system includes the esophagus.
The __________ system includes the brain.
Which system carries food and oxygen to cells?
What structures work in antagonistic pairs to move bones?
How many bones does a human adult have?
How do muscles work in antagonistic pairs?
when one muscle pulls, the other muscle relaxes
What is the function of cartilage in adult bones?
preventing friction between bones
Which is the most common type of muscle in the body?
Food moves through the digestive tract by peristalsis, which is produced by wavelike contractions of _________ muscles.
What is the function of spongy material called red marrow?
it makes blood cells
Which skeletal structure encloses the reproductive organs?
Which type of muscle is found in the lining of the arteries?
Which structure is an example of a hinge joint?
How many bones does an infant have at birth?
The walls of arteries include a ________ muscle layer.
Where in the body is cardiac muscle found?
What is not a function of the skeletal system?
Which organ is involved in ingestion?
What happens to food material that cannot be digested?
it is eliminated as feces
Food moves from the mouth to the stomach through which organ?
Which organ stores and releases bile?
Which shows the correct order in which food moves during digestion?
stomach, small intestine, large intestine
The third stage of digestion is absorption, which begins when the food enters the _________.
Which organ forms the largest section of the digestive tract?
During digestion, excess glucose is stored in liver cells and muscle cells in what form?
Food travels directly from the stomach to the _________.
Which event occurs in the large intestine?
water is recovered
Which structure helps food move to the pharynx?
Which organ is at the end of the digestive tract?
Where does the digestive process begin?
in the mouth
Inhalation begins when ________.
the diaphragm contracts
Which statement is not true of cilia in the respiratory tract?
they close the windpipe opening when swallowing
At the tip of each bronchiole is ________.
Which disease causes mucus to build up in the lungs and clog the airways?
Which structure prevents food and liquids from being inhaled when a person swallows?
During inhalation, air moves directly from the larynx to the _________.
Which occurs during inhalation?
the rib cage expands
Where is the diaphragm located?
below the lungs
Which action removes carbon dioxide from the body?
Which structures bring oxygen from the trachea to the lungs?
Which event signals the brain to breathe?
increased blood levels of carbon dioxide
Which is the largest artery in the body?
What is the function of white blood cells?
they fight infections
Which condition causes fatty substances to build up in blood vessels?
What transports oxygen in the blood?
red blood cells
When the left ventricle contracts, blood flows to the ________.
What is the function of interstitial fluid?
it exchanges nutrients and wastes with blood
Fibrinogen is a protein produced in platelets that _______.
creates blood clots
When the ventricles contract, blood flows from the right ventricle to the ________.
A thrombus can clog an artery. What occurs when an artery in the brain is blocked?
Which structure(s) carry oxygen-rich blood away from the heart?
Which lobe in the cerebral cortex is responsible for short-term memory?
A thin membrane stretching across the ear canal is the __________.
How many pairs of spinal nerves branch off from the spinal cord?
Which structure controls the amount of light that enters the eye?
Which type of sensory receptor responds to touch and pressure?
What is the spinal cord?
a thick bundle of nerves
What does the limbic system do?
registers feelings, such as fear and pleasure
What is one function of the backbone?
it protects the spinal cord
Which structure starts at the brain and goes down the back?
the spinal cord
The brain communicates with the rest of the body through the __________.
What is one of the functions controlled by the cerebellum?
Where is the spinal cord found?
in the backbone
Which type of stimulus do mechanoreceptors detect?
Hormones secreted by the hypothalamus __________.
regulate the pituitary gland
What is a function of the hormones secreted by the pancreas?
they regulate blood levels of glucose
What is the term for the chemical messengers that the endocrine glands produce?
In the body, hormones move from one location to another through _________.
Which organ forms urine?
Through which structure does urine leave the body?
Low blood levels of which substance would cause the release of more ADH into the blood?
Which is a way for the body to conserve water during periods of heavy sweating?
it can filter less water out of the blood
Kidneys filter __________ from the blood and form urine.
Which glands produce hormones that increase metabolic activity and increase blood levels of glucose?
the adrenal glands
Which is one way that skin protects the body from infection?
skin keeps germs out of the body
Which cells produce antibodies?
Which is another term for a germ?
How does fever help fight germs?
it stops bacteria from growing
Which activity is part of the inflammatory response?
compliment proteins signaling phagocytes
How do phagocytes protect the body?
they eat infected and foreign cells
Which statement is true of antibodies?
they are specific to antigens
Which is a description of fever?
increased body temperature
Which directly attacks host cells that contain bacteria or viruses?
Each lymphocyte had thousands of receptor proteins in its membranes. What is the job of these receptor proteins?
to recognize antigens
When does menstruation occur?
after an egg fails to fertilize
Testosterone is produced in which structure(s)?
The diploid cells that begin spermatogenesis are called spermatogonia. Where are spermatogonia found?
in the seminiferous tubules
Which process occurs when an egg cell, blood, and pieces of uterine lining leave the body through the vagina?
Semen and urine both exit the body through the _________.
What happens during ovulation?
a follicle releases an egg into a fallopian tube
Which structure connects the testes to the urethra?
Where does oogenesis take place?
in the ovaries
Where in the body do oocytes mature?
Where does spermatogenesis take place?