Olympiad Test: Plant Life - 1 - Class 5 MCQ

Signals that show a tree is preparing for winter:

• The days become colder: As winter approaches, the temperature drops, and the tree can sense this change. Cold temperatures trigger physiological responses in the tree, signaling the need to prepare for winter.


• The weather becomes dry: In many regions, winter brings drier conditions compared to other seasons. The tree prepares by reducing its water uptake and conserving moisture to survive during the dry winter period.


• There are more rainy days: While it is true that winter can have more rainy days in some areas, this is not a direct signal of a tree preparing for winter. Rainfall is more related to the local climate and may not directly influence the tree's winter preparations.


• There are fewer hours of sunlight: As winter approaches, the days become shorter, resulting in fewer hours of sunlight. This reduction in sunlight triggers hormonal changes within the tree, leading to the shedding of leaves and the slowing down of growth in preparation for the dormant winter period.

Therefore, among the given options, the correct signal that shows a tree is preparing for winter is: The days become colder.

Why do the leaves of trees change color in the fall?
Answer:
The changing colors of leaves in the fall is a natural process that occurs in deciduous trees. The main reason for this phenomenon is the decrease in chlorophyll production, which is responsible for the green color of leaves during spring and summer. The change in color is a result of various factors, including changes in temperature and daylight hours.
Here is a detailed explanation of why the leaves of trees change color in the fall:
1. Decrease in Chlorophyll:
- Chlorophyll is essential for photosynthesis, the process by which plants convert sunlight into energy.
- During fall, trees start to prepare for winter and reduce their energy production.
- As a result, chlorophyll production decreases, leading to a decline in the green color of leaves.
2. Other Pigments:
- As chlorophyll breaks down, other pigments that were previously masked become visible.
- These pigments include carotenoids (responsible for yellow, orange, and brown colors) and anthocyanins (responsible for red and purple colors).
- The combination of these pigments gives rise to the vibrant hues seen in fall foliage.
3. Temperature and Daylight:
- Temperature and daylight hours play a crucial role in triggering the color change.
- As autumn approaches, the days become shorter, and the nights become cooler.
- This change in environmental conditions signals to the trees that it is time to prepare for winter dormancy.
- The decrease in sunlight and cooler temperatures contribute to the breakdown of chlorophyll and the activation of other pigments.
4. Environmental Factors:
- Environmental factors such as soil moisture, nutrient availability, and weather conditions can also influence the intensity and duration of fall colors.
- Drought or stress can cause leaves to change color earlier or drop prematurely.
In conclusion, the changing colors of leaves in the fall occur due to a decrease in chlorophyll production, which unveils other pigments that were previously masked. This process is triggered by changes in temperature, daylight, and various environmental factors. The beautiful array of fall foliage is a remarkable natural phenomenon that marks the transition from summer to winter.

Introduction:
When a mango sapling grows too close to its parent tree, it can face several challenges that may hinder its growth and development. Let's explore these challenges and their impacts on the sapling.
Reasons:
There are three main reasons why a mango sapling growing near its parent tree may face difficulties:
1. Limited Branch Spread:
When a sapling grows too near to the parent tree, it may not have enough space to spread its branches. This can result in stunted growth and restricted access to sunlight and air circulation.
2. Inadequate Water Supply:
The parent tree may consume a significant portion of the available water in the soil. As a result, the sapling growing close to the parent tree may not receive sufficient water for its own growth and survival.
3. Insufficient Sunlight:
The parent tree's canopy can block sunlight from reaching the sapling growing beneath it. Lack of sunlight can hamper the sapling's ability to carry out photosynthesis, which is essential for energy production and overall growth.
Impacts:
The combined effect of these challenges can have detrimental consequences for the mango sapling:
- Restricted branch spread limits the sapling's ability to develop a strong and robust structure.
- Inadequate water supply can lead to wilting, dehydration, and overall poor health of the sapling.
- Insufficient sunlight can result in weak and pale leaves, reduced photosynthesis, and decreased energy production.
Conclusion:
In conclusion, when a mango sapling grows too near to its parent tree, it may face the challenges of limited branch spread, inadequate water supply, and insufficient sunlight. These challenges can hinder the sapling's growth and overall development. To ensure healthy growth, it is advisable to plant mango saplings at a suitable distance from their parent trees.

Roots of plants absorb both nutrients and water from the soil.
- Nutrients: The roots of plants absorb essential nutrients from the soil, which are necessary for their growth and development. These nutrients include nitrogen, phosphorus, potassium, calcium, magnesium, and many others. Plants require these nutrients to carry out various metabolic processes and to build their tissues.
- Water: Roots also absorb water from the soil. Water serves as a solvent and helps transport nutrients throughout the plant. It is essential for maintaining turgidity and cell structure in plants. Water is taken up by the roots through a process called osmosis, where water molecules move from an area of higher concentration (in the soil) to an area of lower concentration (in the roots).
- Both A and B: Therefore, the correct answer is option C, as the roots of plants absorb both nutrients and water from the soil. These absorbed substances are then transported through the plant's vascular system to provide nourishment and support its growth.
- None of the above: Option D is incorrect because roots play a crucial role in absorbing essential substances from the soil for the plant's survival and growth.

Explanation:
The correct answer is B: Layering.
Layering is a method of plant propagation in which a stem of a plant is bent down and buried partially in the soil while still attached to the parent plant. The buried portion of the stem develops roots, allowing it to grow into a new plant. This method is commonly used for plants that have flexible stems, such as blackberries, raspberries, and some indoor plants.
Here is a detailed explanation of the other options:
- Cutting: Cutting is a method of plant propagation where a piece of the stem or leaf is cut off from the parent plant and rooted to produce a new plant. This method is commonly used for plants with woody stems, such as roses or fruit trees.
- Budding: Budding is a form of grafting in which a bud from one plant is inserted into the bark of another plant. The bud then grows into a new plant. This method is commonly used in fruit tree propagation.
- A and B both: This option is incorrect because cutting and layering are two different methods of plant propagation. Cutting involves detaching a portion of the stem from the parent plant, while layering keeps the stem attached.
In conclusion, the method in which the stem of a plant is used to produce a new plant without detaching it from the plant is called layering.

The tribal people rely on various sources to obtain their food. These sources include:
1. Gathering from trees:
- Many tribal communities have extensive knowledge of edible plants and fruits in their local environment.
- They gather fruits, nuts, seeds, and other edible parts from trees and plants found in forests or nearby areas.
2. Hunting animals:
- Hunting is another important method of acquiring food for tribal people.
- They use traditional hunting techniques and tools like bows, arrows, spears, traps, and snares to catch animals for food.
- The animals they hunt may include deer, boars, rabbits, birds, and fish.
3. Fishing:
- Tribal communities living near rivers, lakes, or coastal areas often engage in fishing to supplement their diet.
- They use traditional methods such as nets, traps, and fishing lines to catch fish and other aquatic creatures.
4. Agriculture and farming:
- Some tribal groups practice small-scale agriculture and farming.
- They grow crops like rice, maize, millets, and vegetables for their sustenance.
- These communities often rely on traditional farming techniques and may not use modern agricultural practices.
5. Livestock rearing:
- Some tribal communities rear livestock such as goats, sheep, chickens, and cows for food.
- They obtain milk, meat, and other animal products from their livestock.
6. Exchange/trade:
- In certain cases, tribal people may engage in trade or exchange with neighboring communities to acquire food items they do not have access to.
- This can include exchanging agricultural products, handicrafts, or other goods for food.
7. Limited access to groceries:
- While some tribal communities may have limited access to groceries or marketplaces, it is not their primary source of food.
- They often rely on traditional methods of food procurement instead of purchasing groceries.
In conclusion, tribal people obtain their food through a combination of gathering from trees, hunting animals, fishing, agriculture, livestock rearing, trade, and limited access to groceries. These methods vary depending on the specific tribal community and their geographical location.

Answer:
Bryophyllum is a type of plant that belongs to the Crassulaceae family. It is commonly known as the "Mother of Thousands" or "Mother of Millions" due to its ability to produce numerous plantlets along the edges of its leaves.
From which part of the plant does Bryophyllum grows?
Bryophyllum primarily grows from the leaves of the plant. Each leaf of Bryophyllum has small notches along its edges, and these notches are where the plantlets develop. When these notches come into contact with soil or any suitable growing medium, they can root and grow into new plants.
Some key points to note about Bryophyllum and its growth pattern:
- Bryophyllum is an example of vegetative propagation, where new plants are produced asexually from the parent plant.
- The ability to grow new plants from its leaves gives Bryophyllum a unique reproductive advantage.
- The plantlets that grow from the leaves of Bryophyllum are capable of developing roots and growing into fully independent plants.
- This method of reproduction allows Bryophyllum to spread rapidly and colonize new areas.
In conclusion, Bryophyllum primarily grows from the leaves of the plant, where small plantlets develop along the notches of the leaves. These plantlets can root and grow into new, independent plants.

Plants that need clayey soil to grow well:

• Rice: Rice is a staple food for many people around the world, and it thrives in clayey soil due to its ability to hold moisture. Clayey soil provides good water retention, which is essential for the growth of rice plants.


• Jute: Jute is a fiber crop that is used for making various products like bags, ropes, and textiles. It requires clayey soil with good drainage for its proper growth and development.

These plants specifically require clayey soil because:

• Water retention: Clayey soil has small particles that can hold water for a longer duration, ensuring a constant supply of moisture to the plant roots.


• Nutrient availability: Clayey soil is rich in nutrients and minerals, providing a favorable environment for plant growth.


• Root anchorage: Clayey soil has a compact structure that provides stability to the plant roots, preventing them from being easily uprooted by wind or other external factors.

Other plants, such as wheat and gram, prefer loamy soil, which is a mixture of clay, sand, and silt. Clayey soil may not be suitable for their growth as it tends to retain too much water and can lead to waterlogging, which is detrimental to these crops.

It is important to note that while these plants generally prefer clayey soil, they can still grow in other soil types with proper care and management. Soil quality can be improved through various techniques such as adding organic matter, practicing proper irrigation, and implementing effective drainage systems.

The seed with thick fibrous outer covering is:
Answer: B: Coconut
Explanation:
The seed with a thick fibrous outer covering is the coconut. Here is a detailed explanation:
1. Seed Structure: Seeds are the reproductive structures of plants that contain an embryo, stored food, and a protective outer covering.
2. Seed Coat: The outer covering of a seed is known as the seed coat or testa. It protects the embryo and the endosperm inside.
3. Coconut Seed: The coconut is a large seed with a thick fibrous outer covering, which is the husk or the mesocarp.
4. Husk: The husk of the coconut is made up of tough fibers that surround the inner shell. It is thick and fibrous, providing protection to the inner parts of the seed.
5. Endosperm: Inside the husk, there is a hard inner shell that encloses the endosperm. The endosperm is the nutritive tissue that provides nourishment to the developing embryo.
6. Embryo: The embryo is the developing plant inside the seed. It contains the embryonic shoot (plumule) and the embryonic root (radicle).
7. Coconut Uses: Coconuts are widely used for their water, meat, and oil. The thick fibrous husk also has various uses, such as making ropes, mats, and other natural products.
In conclusion, the coconut has a thick fibrous outer covering, which is the husk or mesocarp. This fibrous husk provides protection to the inner parts of the seed, including the endosperm and the developing embryo.

The part of the seed that stores food is the cotyledon.
The cotyledon is the seed leaf or the primary leaf of the embryo in the seed. It is responsible for storing food that is needed for the growth of the plant until it can photosynthesize and produce its own food.
Here are some key points about the cotyledon:
- The cotyledon is found in the embryo of the seed and is usually the first part to emerge during germination.
- It is responsible for absorbing and storing nutrients from the endosperm or the surrounding tissues of the seed.
- The stored food in the cotyledon provides energy for the growth of the seedling until it can develop true leaves and start photosynthesis.
- In some plants, such as dicots, the cotyledon remains in the seed and becomes the first leaves of the plant, while in others, such as monocots, the cotyledon is absorbed by the growing seedling.
- The number of cotyledons varies among different plant species. For example, dicots typically have two cotyledons, while monocots usually have one.
In summary, the cotyledon is the part of the seed that stores food and provides energy for the initial growth of the plant until it can produce its own food through photosynthesis.