According to the fossil records, the ancestors of land plants were aquatic organisms that resemble the green algae.

B. an organism similar to green algae

Choices B, C, and D are all incorrect. In order to classify the plant kingdom into specific taxonomic categories, scientists observed and studied the DNA sequences of various plant species.

A. studies comparing DNA sequences

A sporophyte undergoes a diploid phase, wherein meiosis produces spores. On the other hand, a haploid phase occurs when a gametophyte produces reproductive cells or gametes.

C. A sporophyte is the diploid phase, while a gametophyte is the haploid phase of the plant life cycle.

Plants have basic needs, such as sunlight, carbon dioxide, and water, in order to survive and conduct photosynthesis. Photosynthesis allows plants to manufacture glucose and store it as chemical energy.

According to the diagram, the ancestors of land plants were closely related to the green algae. This matches with the fossil records that say the plant ancestors were aquatic organisms that resemble the modern green algae.

The lack of vascular tissue or true water-conducting tissue is the characteristic that makes the mosses plant different from the fern plant.

Ferns live suitably in moist or damp places. They favor this kind of environment because it allows them to reproduce. When they undergo fertilization, the water enables the sperm to swim and fertilize the eggs.

B. The sperm of bryophytes need water to swim an egg.

Choices A, B, and C are all incorrect. A transport tissue called xylem carries the water in an upward manner from the roots into the other parts of the plants.

D. xylem

In seed plants, such as gymnosperms and angiosperms, the embryo develops inside the reproductive structures of the plant. Unlike ferns and mosses, seed plants have the ability to reproduce without water.

C. their gametes do not require water for fertilization to occur

Mosses favor a moist or damp environment because it allows them to reproduce. When they undergo fertilization, the water enables the sperm to swim and fertilize the eggs.

The significant role of lignin in plants is to support the vascular tissues by filling the cell wall. It also prevents the absorption of water in the cell walls in order to allow an efficient transfer within the tissues and to avoid the collapse of the cells.

A coniferous tree’s life cycle takes two years to complete because that is also the same amount of time it takes for the seeds inside the cone to grow and become mature. Once they are fully matured, they are ready to leave the cone.

During meiosis, the spores produced by a fern plant grows into heart-shaped gametophytes. These gametophytes contain archegonium, which is the female reproductive organ that produces the eggs, and antheridium, which is the male reproductive organ that produces the sperm.

Stamens are the male reproductive parts of the flower which consist of the filament and the anther. Anthers produce the pollen grains, which are the male gametophytes. On the other hand, carpels are the female reproductive structures that produce female gametophytes and seeds. These structures consist of the stigma, style, and the ovary.

A. anthers

Vegetative reproduction is a process wherein flowering plants reproduce asexually through mitosis and it does not require fertilization and the help of gametes, seeds, or flowers. It results in the production of a plant’s genetically identical offspring.

D. vegetative reproduction

After a successful fertilization, the angiosperm seeds start to mature. During this process, fruits are formed when the ovary walls, which enclose the seeds, begin to thicken.

A. fruit

Carpels are the female reproductive structures that produce female gametophytes and seeds. It is located at the innermost part of a flower. The carpel, together with the stigma, style, and ovary, are sometimes referred to as a whole unit, which is called pistil.

Angiosperms undergo double fertilization that involves the production of a diploid zygote when sperm and egg cell combine and a triploid cell, which later becomes an endosperm when the sperm fuses with two polar nuclei.

Plants need the help of animals, wind, and water when it comes to seed dispersal.

a. Animals: After the animals consume the fruits, the seeds are digested and eliminated from the body through their feces. On the other hand, some seeds are dispersed when they get tangled in the fur or feathers of animals.
Examples of plants that are dispersed by animals: Apples, cherries, and blackberries

b. Wind: Seeds that contain feathery bristles are often blown or carried by the wind. This enables the seeds to be transported into distant places.
Examples of plants that are dispersed by the wind: Dandelion and maples

c. Water: Oftentimes, seeds of plants that thrive near or within an aquatic environment rely on water for seed dispersal. Seeds that are light and waterproof stay afloat and are usually transported into different places through the help of the water.
Examples of plants that are dispersed by the water: Water lilies, mangrove, coconut, and other palm trees

The adaptation in which seeds are prevented from germinating during an unfavorable condition is called seed dormancy. In this stage, the seeds enter a state wherein their growth and development are temporarily stopped. This allows the seed to survive the harsh environment and grow at a later time when the situation is more ideal.

a. The answer is C. The oval-shaped structure in the stamen is called an anther. This structure is where the pollen is produced.

b. Label A represents the style. It is the stalk that holds the stigma and connects it to the ovary of the flower.

c. The answer is F. The ovary is the female reproductive part of the flower that produces an ovule. Once it is fertilized, it develops into seeds.

d. The answer is sepal. Sepals are the modified leaves that are found at the outermost part of the flower. Their function is to protect a young, developing flower.

The letters below represent the parts of the flower in the diagram:

A – Style
B – Stigma
C – Anther
D – Filament
E – Stamen
F – Ovary
G – Sepal
H – Petal

a. The answer is C. The oval-shaped structure in the stamen is called an anther. This structure is where the pollen is produced.

b. Label A represents the style. It is the stalk that holds the stigma and connects it to the ovary of the flower.

c. The answer is F. The ovary is the female reproductive part of the flower that produces an ovule. Once it is fertilized, it develops into seeds.

d. The answer is sepal. Sepals are the modified leaves that are found at the outermost part of the flower. Their function is to protect a young, developing flower.

Scientists grouped the plants by identifying their embryo formation, specialized water-conducting tissues, seeds, and flowers. Moreover, in order to classify the plants into more specific taxonomic categories, they have also observed and studied the DNA sequences of various plant species.

A multicellular haploid plant is referred to as the gametophyte. The gametophyte stage is the most dominant phase in the life cycle of a bryophyte.

The difference between the alternation of generations between mosses and flowering plants is the relative sizes of the haploid (gametophyte) and diploid (sporophyte) stages. The gametophyte stage is the most dominant phase in the life cycle of mosses. Unlike mosses and other bryophytes, flowering plants have the sporophyte stage as the most dominant phase in their life cycle.

Algae are similar to plants in such a way that they are both photosynthetic eukaryotes. Moreover, there is a presence of a cell wall and chlorophyll on both organisms. However, there are several differences in terms of the physical structure and reproductive function of the two organisms. Algae, which are non-vascular, lack roots, stems, and leaves, whereas plants have these structures. Algae produce spores and not seeds. On the other hand, plants grow and develop their embryo or seeds inside them.

Mosses and other bryophytes are generally small in height because they lack the vascular and other supporting tissues that allow plants to draw water up against the downward pull of gravity.

On the other hand, fern plants grow taller than mosses because they have an evolved transport system. The presence of vascular tissues and specialized cells that are strengthened by lignin allows them to move or transport water and nutrients throughout the parts of the plants.

The two transport systems, which are similar to the function of the circulatory system in animals, move different substances throughout the parts of the plant. The xylem tissues transport water and mineral ions, whereas the phloem tissues transport the products of photosynthesis, such as nutrients and carbohydrates. It is efficient to use two transport systems because they can move the water and nutrients against gravity.

A seed is considered a reproductive structure since it is a plant embryo that has the potential to become a new plant. It is ready to sprout as soon as it meets the required conditions for growth.

By the time the Mesozoic Era came, living things had developed adaptations suited for the life on land instead of being confined to the oceans. This change indicates that a major characteristic of the plant kingdom is that they are stationary. To compensate for not being able to move on their own, they have special adaptations, which are distinct from one other, in order to survive.

In the beginning, mosses dominated the land but they were just confined to damp and moist areas. However, the climate during this period was warmer than the modern-day climate. The warmth and humidity affected the forest life. As a result, plants developed adaptations that would allow them to draw water from the soil. This event led to the appearance of plants that have vascular transport system. These plants are the ferns, horsetails, and club mosses.

Bryophytes would live suitably in moist or damp places. They favor this kind of environment because it allows them to draw water directly from the damp soil because they lack the vascular tissues that make plants draw water against the gravity. In addition, water is required for their reproduction. When they undergo fertilization, the water enables the sperm to swim and fertilize the eggs.

The adaptation in which the seeds of lupine are prevented from germination during a particular condition is called seed dormancy. In this stage, the seeds experience a temporary absence of growth and development to allow the seeds to hinder germination when unfavorable conditions exist. As a result, this helps the seed survive the harsh environment and grow at a later time when the situation is more ideal; hence, their survival rate increases.

Since gymnosperms produce two types of cones–male pollen cone and female seed cone, adding a second pine cone in the model would allow the student to familiarize himself with the structure of the two cones and to differentiate them from one another. It would also help him imitate the life cycle of a conifer, particularly its pollination and fertilization stages.

Fruits are usually formed within the female reproductive part of the flower. After the successful fertilization, the angiosperm seeds start to mature inside the ovary. During this process, fruits are formed when the ovary walls, which enclose the seeds, begin to thicken. In this case, since a stamen serves as the male reproductive part of a flower, seeds cannot grow in it. Therefore, the answer is no.

Since seeds are mostly made up of hard tissues that can be preserved as fossils, they serve as clues that tell the scientists about the past environment. They can tell the numerous plants that served as an important part of the plant food diet by the organisms from the past.

Moreover, seeds contain plant embryos that are usually dormant. This function allows them to hinder germination when unfavorable conditions exist. As a result, this helps the seed survive the harsh environment and grow at a later time when the situation is more ideal; hence, they are preserved and they last longer.

The characteristics that are shared by an oak tree and a zebra is that they are both multicellular organisms and they are both made up of eukaryotic cells. These organisms undergo life cycles and they carry out life processes in order to survive.

On the other hand, an oak tree is a member of the plant kingdom. The characteristic that sets them apart from other organisms is that they are immobile. To compensate for not being able to move on their own, they are autotrophs. They are able to conduct photosynthesis to manufacture their own food.

Here are the advantages and disadvantages of sexual reproduction and vegetative reproduction:

Sexual Reproduction:
a. Advantages: There is an increased diversity among organisms due to fertilization of male and female gametophytes. In addition, the embryo develops inside the female plant, which protects them from the harsh conditions in the external environment.
b. Disadvantages: Plants that undergo sexual reproduction reproduce less frequently. In addition, mutations and poor traits can be passed on to the offspring.

Vegetative Reproduction:
a. Advantages: It does not require fertilization and the help of gametes, seeds, or flowers. In this case, plants that have desirable traits are easily reproduced and reproduction happens at a faster rate.
b. Disadvantages: Since the offspring are genetically identical to the parent, there is no diversity among the plants.

According to the table, the seed of the Norway maple is likely to be carried farthest from the parent tree. The average time for the seed to fall from a height of 4 meters is 5.2 seconds. If it is carried at a distance of 1.5 meters for every second, then it would reach 7.8 meters away from the parent tree.

Furthermore, its wing-like structure creates an advantage for seed dispersal. It allows them to glide to a farther distance due to the wings that make the fruit spin and twirl when blown by the wind.

According to the illustration on the table, the seeds from the shagbark hickory and red oak trees do not depend solely on the wind for dispersal. They do not have winged-structures that allow them to glide to a farther distance when they are blown by the wind. Instead, they depend on other seed dispersal agents like animals to take them in farther distances.

D. Red oak and hickory depend on factors other than wind to achieve dispersal.

Since mosses thrive well in moist and damp places, they grow abundantly in shaded areas, which are not exposed to direct sunlight. At the sixth year, the area of moss in sun reached 1 square meter, whereas the area of moss in shade reached 9 square meters. Therefore, the growth of moss in shade is greater than the growth of moss in sun.

Mosses live suitably in moist or damp places. They favor this kind of environment because it allows them to draw water directly from the damp soil because they lack the vascular tissues that make plants draw water against the gravity. This also helps them during reproduction since the sperm needs to swim to the eggs for fertilization.

If they are exposed to the sun, the water in the soil would evaporate and the soil would become dry. This condition is not optimal for the survival and reproduction of mosses. On the other hand, if the area is shaded, the soil moisture would be retained; hence, there is an abundant growth of mosses.

The seeds of angiosperms undergo double fertilization that consists of these events:
1. When the pollen grain’s generative cell travels into the ovary, it divides mitotically to form two sperm nuclei.
2. In the ovule, one of the sperm nuclei combines with an egg cell to produce of a diploid zygote.
3. The other sperm nuclei fuse with two polar nuclei, the production of a triploid cell takes place.
4. The triploid cell becomes the endosperm tissue, which is the nutrient source for the growing embryo.
5. After fertilization, the ovule develops into seeds.

Here are the steps on how to distinguish the major types of plants:

1. Determine the environment where the plant is found.
a. Green algae are mostly aquatic. They either live in the freshwater, saltwater, and other wet habitats.
b. Mosses and ferns live suitably in moist and damp places.
c. Gymnosperms and angiosperms live mostly in dry habitats.

2. Determine if the plant has true roots, leaves, and vascular tissues.
a. Green algae and mosses do not have true roots, leaves, and vascular tissues.
b. Ferns, gymnosperms, and angiosperms have true roots, leaves, and vascular tissues.

3. Determine whether the plant reproduces by spores or seeds.
a. Green algae, mosses, and ferns are spore-bearing plants.
b. Gymnosperms and angiosperms are seed-bearing plants.

4. Determine whether the plant bears the seeds in cones or flowers.
a. Gymnosperms bear their seeds in cones.
b. Angiosperms bear their seeds in cones.

Aside from attracting pollinators to the plants, flowers aid in the reproductive success of plants by protecting the embryo from the presence of harsh elements on land. Since flowers are the reproductive parts of the plant, this is where fertilization takes place. Unlike green algae, mosses, and ferns that need water for reproduction, flowering-plants do not require water in order to reproduce an offspring. These conditions allowed the angiosperms to be successful in surviving the terrestrial life.