One of the main structures present in plants is **stem**. The stem is the main stalk of a plant that supports the leaves and conducts water and minerals in the whole organism. Hence, the correct answer is **B**

B

**Meristem or Meristematic tissue** is a kind of tissue found in plants that consist of undifferentiated cells that are capable of cell division. Meristem can form into all kinds of tissues and organs that are present in plants.

Meristerm is grouped as apical, laterial and intercarlary meristem
**Apical meristem** is the growth region in plants that can be found in *root tips*, *stem hoots*, and *leaves*, just like in the diagram presented. Hence, the correct answer is **A**

A

**Vascular tissue** is a complex transporting tissue of plants that functions in the conduction of fluid and nutrients in the plant internally. The two main components of vascular tissue are **xylem** and **phloem**. **Phloem** transports amino acids and sugar between leaves and other parts of the plant. Hence, the correct answer is **C**

C

**Vascular bundle** is the structure of conducting vessels present in the stem or leaves of the plant. It is composed of different vascular tissues working together. One vascular tissue present in the bundle is the *xylem*– it is composed of tracheids and vessel elements that enable it to transport water in the plant. Hence, the correct answer is **C**

C

The Casparian strip is a hydrophobic feature in the cell walls of a root that surrounds the endodermis.

C. Casparian strip

The secondary growth of a plant happens in the vascular cambium. When the vascular cambium produces more tissues, it makes the stems thicker over time.

A. vascular cambium

The spongy mesophyll, which is located beneath the palisade layer, contains air spaces that are connected to the stomata.

B. spongy mesophyll

The guard cells, which are found in the stomata, contains a turgor pressure that controls the opening and closing of the stomata.

C. guard cells

Phloem carries the nutrients and the products of photosynthesis throughout the plant.

B. phloem

For tall plants, root pressure and capillary action are both insufficient to lift the water at a certain height. Therefore, the root pressure and the force of transpiration pull are both needed in order to move the water to the topmost part of a tall plant.

D. transpiration pull

Xylem tissues carry water from the roots going upward to the other parts of the plant. It consists of specialized cells called tracheids and vessel elements. They are both involved in the movement of water throughout the plant.

Phloem tissues carry 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.

Parenchyma: It is where photosynthesis takes place in the leaves of a plant.

Collenchyma: This cell has flexible and strong cell walls that function to support plants that are larger in size.

Sclerenchyma: This cell has rigid cell walls that make the ground tissues have a tougher texture.

Dicot roots have a central column of xylem cells, arranged in a radiating pattern. While dicot stems have vascular bundles that are arranged in an organized ringlike pattern.

**Root hairs** are the tubular outgrowth of the roots specifically the trichoblast (the hair-forming cells). These structures are usually lateral extensions and rarely branched.

Root hairs are also known as “*absorbent hair*s” since they greatly elevate the surface are of the roots, therefore facilitating more absorption of water and minerals in the soil

The secondary growth of a plant happens in the vascular cambium. When the vascular cambium produces more tissues, it makes the stems thicker over time.

The bark is formed from the phloem, cork cambium and cork tissues

see explanation for solution

**Leaves** are the flattened structure of a plant, usually green in color and blade-like in shape. Some are directly attached into the stem of a plant and others via connecting stalk.

**Leaves** main function are for **photosynthesis** and **homeostasis**. The leaves carry chloroplast and stomata which is important in the absorption of light energy and gas exchange in the plants.

The function of the cuticle and the epidermis layer is to form protective layer over the leaves to prevent the loss of nutrients and water. The pore like openings allows the exchange of oxygen and carbon dioxide, and the controlled release of water

The property of water that is essential in its upward movement in a plant is the capillary action caused by adhesion. Capillary action is the movement of the water molecules across the surface of plant tissues caused by the adhesion between the two.

The guard cells, which are found in the stomata, contains a turgor pressure that controls the opening and closing of the stomata to regulate the rate of transpiration in plants. If a plant loses too much water due to uncontrolled transpiration, it will start to wilt.

Phloem tissues carry 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.

**Source cells** are cells that produce and release sugar for the plant. These cells can be found in leaves, where photosynthesis occurs. On the other hand, **sink cells** are the recipient cells of the sugar delivery. Sink cells can be found in the roots or shoots of the plants.

In plants, the stems grow in two ways – primary growth and secondary growth. The primary growth is produced by the apical meristem located at the topmost part of the stem. Cutting this will inhibit a plant to grow vertically. On the other hand, the secondary growth of a plant happens in the vascular cambium. When the vascular cambium produces more tissues, it makes the stems thicker over time. This is responsible for the lateral growth or the increasing diameter of plants.

In the roots of a plant, the endodermis cells, which encloses the vascular cylinder, are involved in the uptake of nutrients and water from the soil.

In the stems of a plant, the phloem tissues have sieve tube elements, which are the specialized cells involved in transferring the molecules to the other parts of the plant.

In the leaves of a plant, the guard cells, which are found in the stomata, contains a turgor pressure that controls the opening and closing of the stomata to regulate the rate of transpiration in plants.

Casparian strips aid in the one-way or upward movement of water molecules in the vascular cylinder of the roots. Since the strips have a hydrophobic feature that gives a wax-like texture in the cell walls of the roots, it prevents backflow by helping contain the water inside the vascular cylinder.

The graph show the correlation between the transpiration rate and the water intake of a plant in a given amount of time. The values in the y-axis show the relative rate using the unit g water/2 hr, while the values in the x-axis show the time.

Transpiration is the exit of water molecules from a plant through the stomata of the leaves. This usually takes place during the hottest and driest part of the day, usually noon. At this point, the stomata close to prevent water loss.

The graph shows that that the red line representing transpiration reaches its peak shortly after 12:00 pm. It is at this point that the transpiration rate is the highest and the amount of water loss is at its greatest.

Transpiration is the exiting of water molecules from a plant through the stomata of the leaves. This usually takes place during the hottest and driest part of the day, usually noon. At this point, the stomata close to prevent water loss.

According to the graph, transpiration in this particular case reaches its peak in the late afternoon. At this point, the graph indicates that the plant is losing roughly 30 grams of water every two hours. Fortunately for the plant, the stomata close and reduce the amount of transpiration to keep the plant from losing too much water.

Transpiration, the loss of water as water vapor through a plant’s leaves, decreases the water pressure within a plant and causes internal plant cells to dry out. This results in the plant drawing up more water through its roots as it attempts to replenish its lost water.

The graph indicates that the water intake increases in response to the increasing transpiration.It continues to increase for a short period after the transpiration reaches its peak. This illustrates the relationship that the amount of water intake in a plant is stimulated by changes in transpiratory activity.

Desert plants, such as cactus, have smaller and fewer stomata than other plants. The stomata cells are also situated deep in the tissues of the cactus. Since the desert has an arid environment, having this kind of adaptation allows the cactus to reduce water loss and keeps the hot wind away from the drying up the stomata in the leaves.

On the other hand, a coniferous plant, such as a juniper, thrives in a temperate region. Junipers have leaves that are reduced to tiny, waxy scales which can cover the twigs and small branches to avoid desiccation and to protect the plant against the cold weather.

Secondary growth is a measure of the width and thickness of a plant’s stem. As the plant grows from year to year the increase in width causes rings to form. Most studies conducted to investigate a plant’s age involve counting the number of rings present in a tree stump to determine the tree’s age.

An experiment to determine the relationship between a plant’s secondary growth and its lifespan would involve taking care of a set of dicot plants for a certain amount of time and then cutting them down at various intervals. The experimenter would then count the number of rings to measure the amount of time that the plants had grown.
Prior to cutting, the experimenter would need to measure the circumference and width of the plants. The width and the number of rings could then be plotted on a graph to show the correlation between how long the plant was alive and how much it was able to grow in width.

A leaf is a plant organ that is attached to a stem or a stalk. It usually has a flat and thin structure that functions to absorb light and to process photosynthesis. This is also where transpiration and respiration take place.

A grass is a monocotyledon plant that starts out as a single section but it grows and develops nodes and internodes. During its primary growth, its stem and leaves increase in length at a certain limit since they do not grow very tall. Moreover, their secondary growth produces a fleshy growth. On the other hand, a conifer experiences primary growth in its apical meristem, while the secondary growth occurs in the vascular cambium and cork cambium. When the apical meristem produces tissues, the tree grows taller, whereas the vascular cambium produces more tissues to make the diameter of the stem larger over time.

A tall tree can be relatively similar to a skyscraper in such a way that these two require a great water pressure for an adequate water supply. In skyscrapers, they use pressurized systems to ensure sufficient water pressure. This is extremely important to ensure that the water supply can reach the topmost story of the skyscraper. This is similar to the way a tall tree needs the combined forces of root pressure, capillary action, and transpiration to aid in the upward movement of water molecules to reach all the parts of the tree, including the topmost one.

This is because the sap is triggered by the temperature changes in the environment. When the temperature drops, a pressure develops inside the tree and causes the sap to go from the roots up to the crown. This is why the sap pushes itself out in any holes or crack in the tree. When the early spring comes in, there is a fluctuation in the temperature making it above freezing point and this triggers the sap to come out.