Olympiad Test Level 1: Plants and Animals - Class 3 MCQ

Plants require stem, leaves, roots for its survival. In this, plant (a) does not have roots in it. Plant (b) does not have leaves and plant (c) does not have stem. So only plant (d) can survive because it has all the parts(roots, stem and leaves) in it.

Shoot is the part of the plant which grows above the ground and root is the part of the plant which grows below the ground.

Horse is a plant eater animal so, it is a herbivore.

Animals which eat only plants are called Herbivores. Animals which only eat flesh are called Carnivores. Animals which eat both plants and flesh are called Omnivores.

Whales are marine mammals which give birth to young ones.

Plants are autotrophs or producers which make or manufacture their food by their own.

 Elephants trunk break branches and leaves, it also sucks water and blows into the mouth.

Monkey is an arboreal animal which has a habitat on trees.

Thorns in Desert Plants: Their Function and Importance

Thorns are modified structures found in some desert plants that serve various purposes. In the context of desert environments, where resources like water and nutrients are scarce, thorns play a crucial role in the survival and protection of these plants.

1. Protection against Herbivores:
One of the primary functions of thorns is to protect desert plants from being consumed by herbivorous animals. The sharp, pointed nature of thorns acts as a deterrent, preventing animals from approaching or feeding on the plant. By acting as a physical barrier, thorns help in reducing the risk of damage caused by grazing or browsing animals.

2. Defense against Predators:
In addition to deterring herbivores, thorns also serve as a defense mechanism against predators. Many desert plants with thorns are often avoided by animals due to the potential harm caused by the sharp structures. This helps in safeguarding the plant from being uprooted or damaged by larger animals seeking shelter or food.

3. Reducing Water Loss:
Desert plants face the challenge of water scarcity, and thorns can assist in reducing water loss. By modifying leaves into thorns, the plant decreases its overall surface area exposed to the dry desert air. This adaptation helps to minimize water loss through evaporation, as the reduced surface area reduces the chances of transpiration occurring.

4. Regulating Temperature:
Thorns can also play a role in regulating the temperature of desert plants. In hot desert environments, thorns provide shade to the plant's surface, preventing direct exposure to sunlight. This shade helps in reducing the plant's temperature, minimizing the risk of overheating and excessive water loss through transpiration.

In conclusion, thorns in desert plants have evolved to serve multiple functions, primarily protecting the plant from being eaten by herbivores and defending against predators. Additionally, thorns aid in reducing water loss and regulating temperature, which are vital adaptations for survival in arid desert conditions.

Chameleon is an animal which changes the colour of the body according to its habitat to protect from predators.

Amphibians are carnivores which live both on land and water. These animals lay eggs. Eg. Frog.

Stomata are small openings present on the lower surface of leaves which help in exchange of gases.

The odd one out is: b) Lion

Explanation:

Lions are primarily hunters rather than scavengers, whereas the other animals—crows, vultures, and hyenas—are known to feed on dead animals as part of their diet.

Banana has parallel venation in its leaves as it has a fibrous root system.

Potato is a modified stem and carrot, Radish are roots.

Grass is eaten by Grasshoppers and Frog eats grasshoppers. It is a Food Chain.

1. Outline of a leaf – This corresponds to Margin (c).
2. Exchange of gases – This corresponds to Stomata (d).
3. Broad part of leaf – This corresponds to Lamina (a).
4. Middle line – This corresponds to Vein (b).

So the correct answer is:

Option (d): (i) -c, (ii) -d, (iii) -a, (iv) -b.

Seeds are protected by the fruits.

Solution:

• Statement (i) - True: Fruits are often the fleshy part of a tree that contains seeds.
• Statement (ii) - False: The shoot grows above the ground, not below.
• Statement (iii) - True: The flower is indeed the reproductive part of the plant.
• Statement (iv) - False: Roots absorb water and nutrients (not food) from the soil and transport them throughout the plant, not just to the leaves.

The bark is an outer covering of dead tissue, which protects the trunk of the tree from weather, insects and mechanical injury.