All questions of Plants for Class 4 Exam

Because potato, mushroom and banana do not contain seeds. Also tomato contains seed and is edible to humans too.

It is pine tree as only pine has a fish- bone pattern. So correct option is 'B'.

The main purpose of flowers is to produce seeds for reproduction (Option D is correct). Flowers also have other functions such as attracting pollinators and providing food and nectar for animals, but the primary purpose is reproduction.

Answer:

Introduction:
The plant found in Australia with very few leaves and local people put a thin pipe into the trunk of this tree to drink water is the Oak tree.

About Oak tree:
The Oak tree is a large, strong and long-lived tree. It is a native of the Northern hemisphere and can be found in most parts of the world. In Australia, the Oak tree is known as the Flooded Gum or River Gum. It is found in the eastern half of the country, along the coastal regions and in the drier areas of the interior.

Appearance:
The Oak tree can grow up to 45 meters high and can have a trunk diameter of up to 3 meters. It has a thick, rough bark that is greyish-brown in color. The leaves of the Oak tree are long and narrow, with a dark green color on top and a lighter green underneath. The leaves are arranged in a spiral pattern along the branches.

Adaptation:
The Oak tree has adapted to the Australian climate by having very few leaves. This helps the tree to conserve water in the dry conditions of the Australian landscape. The Oak tree is also able to store water in its trunk, which is why local people can put a thin pipe into the trunk to drink water.

Uses:
The Oak tree has many uses, including being used for timber, firewood, and shade. The timber from the Oak tree is strong and durable, making it ideal for construction and furniture. The Oak tree also provides a habitat for many animals, including birds and insects.

Conclusion:
In conclusion, the plant found in Australia with very few leaves and local people put a thin pipe into the trunk of this tree to drink water is the Oak tree. The Oak tree is a large, strong and long-lived tree that has adapted to the Australian climate by having very few leaves and being able to store water in its trunk. The Oak tree has many uses, including being used for timber, firewood, and shade, and provides a habitat for many animals.

**Leaves**

Leaves are the primary structures in plants that exchange gases, specifically carbon dioxide and oxygen, through tiny openings called stomata. The process of gas exchange in leaves is known as respiration.

**Structure of Leaves**

Leaves are flat, thin, and typically green structures that emerge from stems. They are attached to the stem by a petiole and have a blade-like structure. The blade is the main part of the leaf, and it contains several important components for gas exchange.

**Stomata**

Stomata are small openings found on the surface of leaves. They are surrounded by specialized cells called guard cells, which control their opening and closing. Stomata are vital for gas exchange as they allow carbon dioxide to enter the leaf and oxygen to exit.

**Photosynthesis and Respiration**

Leaves not only exchange gases but also play a crucial role in the process of photosynthesis. During photosynthesis, leaves absorb sunlight, carbon dioxide, and water to produce glucose and oxygen. This process occurs in specialized structures within the leaf called chloroplasts.

On the other hand, during respiration, plants use oxygen and glucose to release energy. Respiration occurs in all living cells, including the cells found in leaves. Oxygen is taken in through the stomata, and carbon dioxide, a waste product of respiration, is released through the same openings.

**Conclusion**

In conclusion, leaves are the structures in plants that primarily exchange gases. They have stomata that allow for the entry of carbon dioxide and the exit of oxygen. Leaves also play a vital role in photosynthesis and respiration, which are essential processes for plant growth and survival.

Water Uptake in Plants
Plants are remarkable organisms that require water for various vital processes. The primary way they absorb water from their surroundings is through their roots.
Role of Roots
- The roots are specialized structures that anchor the plant in the soil.
- They have tiny root hairs that increase the surface area for absorption, allowing them to take in more water and nutrients.
- Water enters the roots through a process called osmosis, where water moves from an area of higher concentration in the soil to an area of lower concentration in the root cells.
Importance of Water
- Water is essential for photosynthesis, the process by which plants convert sunlight into food.
- It helps transport nutrients from the soil throughout the plant.
- Water also provides structural support to plant cells, helping them maintain their shape.
Other Parts of the Plant
- While leaves, stems, and flowers play crucial roles in the plant's life, they do not absorb water directly from the environment.
- Leaves are primarily responsible for photosynthesis and gas exchange.
- Stems serve as conduits for transporting water and nutrients between the roots and leaves.
- Flowers are involved in reproduction and attracting pollinators.
In summary, the correct answer is option 'B' because roots are specifically designed to absorb water from the soil, making them essential for a plant's survival and growth.

Leaves provide the surface area necessary for absorbing sunlight, which begins the process of photosynthesis.

Photosynthesis is the process by which plants, algae, and some bacteria convert sunlight, carbon dioxide, and water into glucose (a form of sugar) and oxygen. This process is essential for the survival of plants and the production of oxygen in the atmosphere.

1. Importance of sunlight for photosynthesis:
Sunlight is the primary source of energy for photosynthesis. The leaves of plants contain a pigment called chlorophyll, which absorbs sunlight. This absorbed sunlight is used to convert carbon dioxide and water into glucose and oxygen. Therefore, leaves need to have a large surface area to maximize their exposure to sunlight.

2. Leaf structure and surface area:
Leaves are flat and thin, providing a large surface area for sunlight absorption. They are typically broad and have a large number of interconnected cells. The upper surface of the leaf is exposed to sunlight, while the lower surface allows for gas exchange. The arrangement of cells and structures like chloroplasts within the leaf further increases the surface area available for sunlight absorption.

3. Role of chlorophyll:
Chlorophyll, the green pigment found in chloroplasts, is responsible for capturing sunlight. It is located in specialized cells called mesophyll cells, which are found in the middle layer of the leaf. The chlorophyll pigments absorb light energy, primarily from the red and blue regions of the electromagnetic spectrum, and transfer it to the chloroplasts. This energy is then used to fuel the process of photosynthesis.

4. Other functions of leaves:
In addition to absorbing sunlight, leaves also play a vital role in the exchange of gases. Through tiny openings called stomata, leaves absorb carbon dioxide (CO2) from the atmosphere, which is necessary for photosynthesis. The stomata also allow for the release of oxygen (O2) produced during photosynthesis and the exchange of water vapor.

Conclusion:
Leaves provide the surface area necessary for the absorption of sunlight, which initiates the process of photosynthesis. Through the presence of chlorophyll and the structure of their cells, leaves maximize their exposure to sunlight and optimize the energy capture needed for photosynthesis. While leaves also absorb carbon dioxide and water, these processes are not the primary purpose of their large surface area.

Mushroom gets its food from:
Dead and decaying plants

Mushrooms are fungi that belong to a separate kingdom called Fungi. Unlike plants, they do not have chlorophyll and cannot carry out photosynthesis to produce their own food. Instead, mushrooms obtain their nutrition from organic matter in their environment, particularly dead and decaying plants.

Decomposers:

Mushrooms are decomposers, which means they play an important role in breaking down organic matter and recycling nutrients in ecosystems. When plants die, their organic material starts to decompose, and mushrooms are one of the organisms that help in this process. They secrete enzymes that break down complex organic compounds present in dead plants into simpler forms that they can absorb and use as food.

Nutrient Absorption:

Mushrooms have a network of fine, thread-like structures called mycelium that spread through the soil or other substrates. The mycelium acts as the feeding structure of the mushroom and is responsible for absorbing nutrients. It grows through the decaying organic matter, releasing enzymes that break down complex molecules into smaller molecules that can be absorbed. The mycelium then takes up these nutrients and transports them to the mushroom's fruiting body, which is the visible part of the mushroom that we usually see.

Role in Ecosystems:

Mushrooms are not only important decomposers, but they also have a symbiotic relationship with plants. Some mushrooms form mycorrhizal associations with the roots of plants, where they exchange nutrients with the plant. In this mutualistic relationship, the mushrooms provide the plant with essential nutrients, such as phosphorus and nitrogen, while the plant provides the mushrooms with carbohydrates produced through photosynthesis.

Conclusion:

In summary, mushrooms obtain their food by decomposing dead and decaying plants. They secrete enzymes to break down organic matter, absorb the nutrients through their mycelium, and transport them to their fruiting bodies. Mushrooms are vital for nutrient cycling in ecosystems and have a symbiotic relationship with plants.

Introduction:
The instrument used to examine the cells of a leaf is a microscope. A microscope is an essential tool for scientists and researchers as it allows them to observe tiny objects and structures that cannot be seen with the naked eye. By using a microscope, we can study the intricate details of cells and understand their functions and characteristics.

Explanation:
Here's a detailed explanation of why a microscope is the correct instrument for examining leaf cells:

1. Magnification:
- A microscope is designed to magnify objects, allowing us to view them in much greater detail.
- Leaf cells are very small, and their structures cannot be seen clearly without magnification.
- The microscope's lenses and eyepiece work together to increase the size of the cells, making them visible to the observer.

2. Resolving Power:
- The resolving power of a microscope refers to its ability to distinguish between two closely spaced objects.
- Leaf cells have various components, such as chloroplasts, nucleus, and cell walls, that need to be observed separately.
- A microscope with high resolving power can distinguish between these structures and provide clear images of individual cells.

3. Types of Microscopes:
- There are different types of microscopes used for examining cells, including light microscopes and electron microscopes.
- Light microscopes use visible light to illuminate the specimen, while electron microscopes use beams of electrons.
- Both types of microscopes can be used to study leaf cells, depending on the level of detail required.

4. Preparation of Leaf Cells:
- Before examining leaf cells under a microscope, they need to be prepared for observation.
- This usually involves obtaining a thin section of the leaf and placing it on a glass slide.
- Staining techniques may also be used to enhance the visibility of certain cell structures.

Conclusion:
In conclusion, a microscope is the instrument used to examine the cells of a leaf. It provides the necessary magnification and resolving power to observe the intricate details of leaf cells. By using a microscope, scientists can study the structure and function of cells, contributing to our understanding of plant biology.

Transpiration is the correct answer.

Explanation:
Transpiration is the process of loss of water through the leaves of a plant. It is an important process in the water cycle, as it helps to maintain the water balance in the environment.

When the water is absorbed by the roots of the plant, it travels up to the leaves through the stem. The water is then released into the air through tiny pores called stomata present on the leaves. This process of water loss through the leaves is called transpiration.

Transpiration plays an important role in regulating the temperature of the plant. As the water is released into the air, it cools down the plant. It also helps in the absorption of nutrients and minerals from the soil by creating a negative pressure in the roots that pulls the water and nutrients up through the plant.

Transpiration also helps in the upward movement of water in the xylem vessels of the plant. This movement of water is essential for the survival of the plant as it helps in the transport of nutrients, minerals, and other essential substances throughout the plant.

In summary, transpiration is the process of loss of water through the leaves of a plant, which helps in regulating the temperature of the plant, absorption of nutrients, and upward movement of water in the plant.

The Correct Answer is Option 'C' (1 and 3)

Explanation:
When the stem of the sunflower plant broke, it caused two major problems for the plant, leading to its death.

1. The plant could not transport food made by the leaves to the rest of the plant:
- The stem of a plant is responsible for transporting food made by the leaves to other parts of the plant.
- This food is produced through a process called photosynthesis, where the leaves use sunlight, water, and carbon dioxide to make food in the form of glucose.
- The food produced in the leaves is transported to different parts of the plant through a tissue called 'phloem' present in the stem.
- However, when the stem breaks, the phloem tissue gets damaged, and the transportation of food is disrupted.
- As a result, the plant cannot get the necessary nutrients and energy to survive and eventually dies.

2. The plant could not transport water from the roots to the leaves:
- The stem also plays a crucial role in transporting water from the roots to the leaves of the plant.
- Water is essential for the plant's growth and survival as it helps in carrying nutrients from the soil to different parts of the plant.
- The stem contains a tissue called 'xylem' that is responsible for upward movement of water.
- However, when the stem breaks, the xylem tissue gets damaged, and the transportation of water is hindered.
- Without a continuous supply of water, the plant's leaves cannot perform photosynthesis effectively, and the plant eventually withers and dies.

In conclusion, when the stem of the sunflower plant broke, it disrupted the transportation of both food and water within the plant. Without a supply of nutrients and water, the plant was unable to survive, leading to its death. Therefore, both option 1 and 3 are correct.

Explanation:
The correct answer is B: 1, 3, and 4.
Reasons:
1. The mushroom feeds on decaying things while the rest do not:
- Mushroom is a decomposer and obtains its nutrients by breaking down dead organic matter. This is known as saprophytic nutrition.
- Coconut tree, cactus, and mimosa are autotrophs that can produce their own food through photosynthesis.
2. The mushroom is a fungus while the rest are not:
- Mushroom belongs to the kingdom Fungi, which is a distinct biological group separate from plants.
- Coconut tree, cactus, and mimosa are all plants belonging to the kingdom Plantae.
3. The mushroom cannot make its own food while the rest can:
- Mushroom lacks chlorophyll, a pigment necessary for photosynthesis, so it cannot make its own food.
- Coconut tree, cactus, and mimosa possess chlorophyll and are capable of photosynthesis to synthesize their own food.
Therefore, mushroom should be categorized differently from the other plants because it feeds on decaying matter, is a fungus, and cannot produce its own food through photosynthesis.