Plants are multicellular eukaryotic organisms that have cell walls made of cellulose. These species are also able to photosynthesize using chlorophyll a and b. Hence, the correct answer is **B**

B

Plants evolved from multicellular photosynthetic organisms that contain the chlorophyll pigment. Among the choices, only green algae have chloroplasts that contain chlorophyll a and b.

B. green algae

**Bryophytes** are considered seedless plants, they are non-vascular plants, one recognizable structure of these species is the presence of the **gametophyte** in their life cycle. Example plants under this Phylum are the **mosses and liverworts**. Hence, the correct answer is **D**

D

Liverworts reproduce asexually using a small reproductive structure called gemmae that came from gemma cups.

C. gemmae

**Vascular bundle** is a structure of conducting vessels present in the stem or leaves of the plant. It is composed of different vascular tissues working together. One of the tissues under this bundle is the *xylem*. **Xylem** is the tissue that transports water and other minerals present in the roots up to other parts of the plant. Hence, the correct answer is **D**

D

**Ferns** are complex nonflowering vascular plants that carry true roots and stems. They use spores for reproduction. The stem of the ferns is called **rhizomes**, while their large leaves are called **fronds**. Hence, the correct answer is **B**.

B

The plant is a liverwort, which is a bryophyte. It is a member of the phylum Hepaticophyta. Liverworts are characterized by their umbrella-like gametophytes.

A. bryophytes

**Cone-bearing** plants have “cones” with seeds (ex. Cycads). They are considered a *naked-seeded* plant since they do not produce fruits or flowers that house the seed. Hence, the correct answer is **D**

D

In angiosperms, mature seeds are enclosed and protected by fruit. When the seeds are immature, they are protected by flower.

C

It is important to know that the lifespan of a certain plant species is dependent on both genetic and environmental factors. Many long-lived plants will continue to grow despite various environmental changes, while short-lived plants will eventually decay after a short period. In relation to this, we can therefore categorize different plant species depending on their life span:

**Biennial** plant species complete their life cycle in two years, then die after the course of the growing season. Biennial plants germinate their roots, stems, and leaves during the first year, then followed by a new stem, new leaves, and flowers during their second year. Hence, the correct answer is **D**

D

During a plant’s life, the plant switches back and forth between haploid form and diploid form using the processes of mitosis and meiosis. This is called alternation of generations.

See explanation.

Plants evolved from photosynthetic plant-like protist called green algae. They are similar in the sense that they are both photosynthetic, have cell wall and similar reproductive system, not to mention the outer appearance.

See explanation.

Plant kingdom is classified according to three characteristics, which are the presence/absence of vascular tissue, seeds, and flower.

See explanation.

Since bryophytes lack vascular tissues, the osmosis process is what they used to draw water to into plants’ leaves. Osmosis is defined as the movement of water from a concentrated area to a non-concentrated area through a semi-permeable membrane

Osmosis

Extreme moisture is needed for mosses to live. In order to reproduce, the sperm has to swim across the water to fertilize the egg. This is why you only find green mosses near waterfalls, streams, or lakes where water is always present.

Protonema is haploid version of moss that appears to be green twisted bunch of filaments, which are produced when the spore lands on moist environmental land and germinates after a few days.

Tracheids are specialized cells in the tree trunk that allow the water to move up efficiently against the gravity. They are just there to conduct water from stem to leaves.

**Lignin** is a complex macromolecule polymer that plays an important role in the rigidity and support of the vascular plant cellular structure, particularly in the formation of its cell wall. LIgnin molecules allow **vascular plants** to be able to grow upright, and expand significantly in size compared to Bryohpytes.

In a fern’s life cycle, the dominant phase is the sporophyte in the diploid phase, wherein the sporophyte plant goes through meiosis to produce haploid spores. When the spores fuse together, a tiny heart-shaped gametophyte plant is formed. A gametophyte plant is under the haploid phase. This part grows independently from the sporophyte.

Rhizoids are slender hair-like structures found in non-vascular plants such as bryophytes and algae. They anchor the body of the plants to the soil and help absorb the water and nutrients.

Rhizomes are a bundle of underground stems that are found in a plant. It forms new shoots and stores protein and starches.

Roots are hair-like structures that are formed in vascular plants like ferns. They have a similar function with rhizoids.

In seed plants, the male gametophyte are hidden in the pollen grain. The role of a male gametophyte is to produce and deliver the sperm cells needed for fertilization.

Conifers’ needle-like leaves that have a thick waxy layer greatly reduce evaporation of water molecules, allowing conifers to live successfully on dry land without being dehydrated. In addition, because they have very thin leaves, that restrict the water molecules from evaporating off.

**Angiosperms** are a group of plant species that developed a unique reproductive structure called the *flower*. These flowering plants are members of the Phylum **Anthophyta** and dominate the earth’s plant life. There are now, 300,000 species of flowering plants on earth.

Angiosperms

Usually, animals eat the fruit near a tree. After traveling a few distances, they release the waste materials from digestion, which contains these seeds that can readily germinate given the proper conditions. This is how the fruit contributes to the dispersal of the plant.

**Monocot** are plants characterized by one or single cotyledon or embryonic leaf. This is a type of flowering plant that have parallel-veins leaves and grass-like vascular bundles in the stem. On the other hand, **Dicot** are plants having two cotyledons or embryonic leaves and roots developed from the radicle. They often possess secondary growth and concentric circles in their vascular bundles, and they contained branched veins.

The drawing below shows the differences between the two types of plants:


Bryophytes: Mosses
Mosses, which are under the phylum Bryophyta, undergo reproduction using spores, and not by seeds or flowers. During mitosis, gametes or haploid cells fuse together to grow a new diploid cell called sporophyte. In turn, this sporophyte grows on top of the gametophyte part of the plant. Mosses are relatively small due to the fact that they lack a vascular system.

Seedless Vascular Plants: Ferns
In a fern’s life cycle, they reproduce by spores. The dominant phase is the sporophyte in the diploid phase, wherein the sporophyte plant goes through meiosis to produce haploid spores. When the spores fuse together, a heart-shaped gametophyte plant is formed. This part grows independently from the sporophyte. The height of a fern can go as little as 1 inch tall and it can be as high as 80 feet.

Gymnosperms: Conifers
Gymnosperms produce through seeds and not by spores. Conifers produce pollen cones that produce pollen grain. Once the pollen is blown to another cone, fertilization will take place. Some conifers such as giant redwoods can grow up to 100 meters.

Angiosperms: Flowering Plants
Angiosperms have flowers as their reproductive structure. Flowers have ovaries which protect the young seeds and later on, these seeds become a fruit after a successful pollination. When the seeds inside the fruit get dispersed, a new plant will emerge.
The size range of angiosperms is very large. It can go as little as half an inch to a hundred feet.

The presence of vascular tissues in ferns has allowed the water and nutrients to be transported from the roots going upward to every part of the plant. As a result, ferns have reached greater heights compared to mosses, which are small in size because they do not have this kind of transport system. They grew in such a way that they are able to get the supply of water and nutrients that they needed. These conditions indicate 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. This creates an interesting plant diversity in the biosphere.

**Bryophytes** are plants that lack vascular tissues in their system and only draw water and nutrients to the process of osmosis. Their life cycle and reproduction are mainly dependent on water, hence these species can be found mostly in moist environments. Therefore, is a person wanted to grown mosses and liverworts in their garden, these should be enough water in the surroundings, and mush as possible no to warm environments.

Angiosperms have become the most numerous plant species on earth because:

1) They develop unique reproductive organs known as **flowers**. Flowers are an advantage to bees, and moths, which then transport pollen from flower to flower. Transfer of pollen with animals is much more efficient than wind pollination

2) Another reason for the success of these plants is their **seeds are enclosed in fruit.** By using fruit, angiosperms attract animals, and angiosperms increase the ranges they inhabit, spreading seeds over hundreds of kilometers.

The cooksonia plant’s recognizable part was the sporophyte phase. It has branches that have capsule-like structures at each end of the stalk. The stalks are considered as the transport system, while the capsules contained sporangium. In this case, this plant reproduces through spores, and not by gametes.

The cooksonia plant resembles the liverworts. Just like the capsule-like reproductive structures in a cooksonia plant, liverworts reproduce asexually using a small reproductive structure called gemmae which came from gemma cups. These plants reproduce using spores, and not by seeds or flowers.

Plants are multicellular eukaryotes that usually carry out photosynthesis in order to survive. They are classified according to the presence or absence of vascular tissues, the presence or absence of seeds, and their reproduction using spores, seeds, or flowers. The four groups of plants include the bryophytes, which includes mosses, liverworts, and hornworts that lack the vascular tissues; seedless vascular plants, including the ferns, club mosses, and horsetails; the seed plants, which include gymnosperms or cone-bearers, and the angiosperms or flowering plants.

Since we usually classify plants based on their appearance and their similarities with other organisms, there are instances that we place them under a group which is not suited to their evolutionary history. An example is a plant called Tmesipteris, which is a fork fern from the fern allies. They are relatives of the ferns but they are not true ferns. They only share similar characteristics in the way they reproduce but they differ in terms of the leaf structure. Because of this, the role of DNA classification has been an effective help in creating a distinction and similarities between the ferns and the fern allies. They were able to determine that the fork ferns closely resembled ferns, which changed the idea that they are actually ferns and not fern allies. By determining the genetic makeup of life-forms, it allowed the scientists to know how they are going to classify organisms.

In a plant’s vascular tissue, there are two transport systems that move water and nutrients all throughout the entire body of a plant. These two transport systems are the xylem and the phloem.

Xylem carries water from the roots going upward to the other parts of the plant. The tracheids are the long cells found in the xylem, while the vessel elements are the shorter and wider cells in the xylem tissue. Both tracheids and vessel elements are involved in the movement of water throughout the plant.

Phloem carries the nutrients and the products of photosynthesis throughout the plant. It has sieve tube elements which are the specialized cells involved in transferring the molecules to the other parts of the plant. The activity of the sieve tube elements is regulated by companion cells.

The orchid shown in the picture is a monocot plant. Normally, the petals found in a monocot are in multiples of three. Since there are six petals in the orchid flower, it fits the category of a monocot.