In class

1. Tick the features that enable a lion to live in a grassland.

Moist skin/ strong legs/ sharp claws/ sharp eyesight

Ans: strong legs, sharp claws, sharp eyesight

2. Animal that live in the mountains have

Long legs and sharp hooves/ thick fur coats/ long ears/ white fur

Ans: thick fur coats.

3 Tropical rainforests have a thick canopy of trees.

True/  false.

Ans: true.

In class

1. How do insects take in air?

Ans: Insects take in air through tiny holes called spiracles present on their bodies.

2. How do ferns reproduce?

Ans: Ferns produce spores on their leaves which give rise to new plants. 

EXERCISE

I. Tick the correct option.

1. What is the habitat of polar bears

Cold mountains/ south polar regions/ north polar regions/ desert region

Ans: north polar region

2. What is the habitat of sharks?

 Lakes/ rivers/ oceans/ ponds

Ans: Oceans 

3. Which of these is not an abiotic components?

Microorganisms/ air/ rocks/ sunlight

Ans: Microorganisms. 

4. Which of these plants are adapted to live in a desert?

Ferns/ cacti/ coconut/ lotus

Ans: Cacti. 

5. What are plants also called?

Heterotrophs/ scavengers/ decomposers/ autotrophs

Ans: autotrophs 

6. What is the movement of ants towards sugar called?

Stimulus/ respiration/ migration/ response

Ans: response.

II. Tick the true statement and cross the false ones.

1. Different habitats support different forms of life.

Ans: True

2. The biotic component of a region includes both animals and plants.

Ans: True

3. The filter-like beaks of ducks help them swim.

Ans: False

4. Animals living in the mountains have very few red blood cells.

Ans: False

5. Mangroves protect coastal regions against cyclones and Tsunamis.

Ans: True

III. Answer the following questions in one sentence.

1. What is a habitat?

Ans: The natural home of a living thing is called the habitat of the living thing.

2. Name the biotic and abiotic components of a habitat.

Ans: Biotic components:- Different plants, animals and other living things.

          Abiotic components:- Air, soil, water, wind, sunlight and heat etc.

3. Why do most cactus plants flower at night?

Ans: Most cactus flower at night to avoid the burning heat of the daytime.

4. How do kangaroo rats obtain water?

Ans: Kangaroo rats obtain water from the food they eat.

5. What are the plants that grow in fresh waterbodies called?

Ans: The plants that grow in fresh waterbodies are called hydrophytes.

6. Why do lotus plants have air spaces in their stems and leaves?

Ans: The air spaces of lotus plants help to stand erect and stay afloat.

IV. Answer the following questions in two sentences.

1. How are the roots of the cactus plants adapted to grow in desert?

Ans: The roots of cactus grow close to the surface and extend over a large area to absorb as much water as possible.

2. Why do tropical rainforests have shade loving plants adapted to grow on the forest floor?

Ans: The broad leaves and overlapping beaches of tropical rainforest form a thick umbrella like roof which block nearly all the sunlight from reaching the forest floor. So the some shade-loving plants grow on the forest floor.

3. List the adaptations that help a lion in grasslands.

Ans: The adaptations that help a lion in grasslands are:

 They have strong legs with sharp claws, strong and sharp teeth and sharp eyesight.

4. Differentiate between autotrophs and heterotrophs.

Ans: Autotrophs: The autotrophs make thir own food by the process of photosynthesis. Plants are autotrophs.

Heterotrophs: The heterotrophs can't make their food on their own, they depends on other animals or plants. Animals are heterotrophs.

5. All living things respond to stimuli. Explain with an example.

Ans: All the living things respond to the stimulus. For example when 'touch me not 'plant is touched then it respond the stimulus by closing its leaves. Here touching the leaves is stimuli and the closing of leaves is the response.

V. Answer in about four to five sentences.

1. Explain how a polar bear is adapted to living in the arctic arctic region.

Ans: A polar bear is adapted to live in the cold arctic region. The adaptations are as follows

         The body of the polar bear is covered with thick layer of hollow hair that traps air. It also has a thick layer of fat below its skin. These keeps the body of a polar bear warm. The polar bear is a good swimmer to catch seals for food. It has a powerful sense of smell. Moreover it conserves energy by sleeping for 7-8 hours every day.

2. Write a short note on plants growing in mountain regions.

Ans: The plants growing in mountain regions have large varieties based on the altitude and temperature difference.

          The outer regions of mountains which are warmer have dense forests of bamboo, oak and chestnut trees.

           As the altitude increases, the temperature drops down, the coniferous and evergreen trees grow. 

            At about 4000 m, the weather becomes too cold so in that region juniper plants grow which are adapted to grow in extreme cold and moist conditions.

3. How are mangrove plants adapted to survive in mangrove swamps?

Ans: The plants of mangroves survive in mangroves swamps by the adaptations in its roots. The roots of the plants grow upward and their tips remain above the surface of water which can breathe air directly from the air.

4. List the adaptations of animals that live in ponds and lake

Ans: The animals in ponds and lakes adapt themselves in many ways. Frogs are adapted to live on land as well as in water. They can breathe air directly from the atmosphere when on land and while in water they obtain oxygen dissolved in water through their moist skin. Many birds living near the ponds and lakes feed on freshwater bodies. So these birds have webbed feet that help them to swim and the filter like beaks help them to feed on small aquatic organisms.

5. List any three common characteristics of living things.

Ans: The common characteristics of living things are

1. Growth 2. Necessity of food and water 3. Movements.