Class 4 Science Lesson 3

Exercise

1. Fill in the blanks by selecting the correct word from the words given below:

water, plants and animals, oxygen, living things, environment, carbon dioxide

a) Living and non-living things together make the environment.

b) Organisms breathe in oxygen gas.

c) Both animals and plants are living things.

d) Plants take carbon dioxide gas from the air when making food.

e) Animals get food from plants and animals.

2. Choose the correct answer from the given options.

a) What does the plant need to prepare its food?

✅ ii. air, water and sunlight

b) Why is soil important for plants?

✅ ii. because it absorbs water and minerals from the soil

c) What do earthworms do to the soil?

✅ ii. make it loose

d) Insects carry…… from one flower of the plant to another.

✅ i. pollen

3. For each of the following statements, mark (V) if they are correct and (x) if they are incorrect: 

a) There is a close relationship between the elements of the environment. (√)

b) Non-living things do not help living things. (X)

c) We get the food and oxygen from plants. (√)

d) All the elements needed by living beings are obtained directly or indirectly from the environment. (√)

e) Animals and plants can survive without water. (X)

4. Answer the following questions:

a) What makes an environment?

👉The environment is made up of living things like animals and plants, and non-living things like air, water, sunlight, and soil.

b) How do animals help plants?

👉Animals help plants by spreading seeds and pollen. Their waste also adds nutrients to the soil.

c) What benefits can we derive from animals?

👉We get food (like milk, eggs, and meat), clothes (like wool and leather), and help in farming and transport from animals.

d) How do bees help the following organisms?

👉i. Humans: Bees give us honey.

Plants: Bees help in pollination, which helps plants grow fruits and seeds.

e) Make a list of environmental factors affecting animals and plants.

• Sunlight
• Water
• Air
• Soil
• Temperature

f) Mention the benefits of sunlight and soil to living things.

👉Sunlight helps plants make food.

Soil gives plants minerals and supports their roots.

g) What does a plant need to make food?

👉A plant needs sunlight, air (carbon dioxide), water, and green leaves to make food.

h) Describe the interrelationship between the organism and the environment.

👉Organisms depend on the environment for food, water, and shelter. In return, they help keep the environment balanced, like trees giving oxygen or animals spreading seeds.

i) Write down how animals and plants can benefit from water. 

👉Plants use water to grow and make food.

Animals drink water to stay alive and clean their bodies.

j) Earthworms are very useful organisms for soil and plants. Justify this statement. 

👉Earthworms make the soil loose and rich in nutrients. This helps plants grow better by getting more air and water.

k) Answer the following questions by looking at the picture: 

i) What process is shown in the picture?

👉 The process shown is photosynthesis. It is the process by which plants make their food using sunlight, carbon dioxide, and water.

ii) What is the function of plant roots in the process of making food?

👉 The roots absorb water and minerals from the soil and send them to the leaves, which are needed to make food.

iii) What is the role of the leaf in the process of making food? 

👉 The leaves take in carbon dioxide from the air and use sunlight to make food. They are the main site for photosynthesis.

l) Write an essay entitled “My Favorite Environment”.

My Favorite Environment

My favorite environment is a green and peaceful garden. It is full of plants, trees, flowers, and birds. I like to sit there and enjoy the fresh air. The garden looks beautiful in the morning with the sunlight shining on the leaves.

In my favorite environment, I can hear birds singing and feel the soft breeze. It makes me happy and relaxed. I also like to plant flowers and water them. Taking care of the garden helps me learn about nature.

The environment is very important for all living things. We should keep it clean and protect it. I love my garden because it is calm, full of life, and helps me feel close to nature.

Exercise

1. Fill in the blanks by selecting the appropriate word from the set of words given alongside:

a) Rapid population growth has negative effect on the environment.

b) Deforestation increases the amount of carbon dioxide in the air.

c) The amount of cultivable land decreases due to urbanization.

d) As the number of people increases, so does the amount of garbage in the environment.

e) Water sources may be drying due to deforestation.

2. Write “True” if the following statements are true and “False” if they are not true. 

a) Population growth does not affect the environment. False

b) As cultivable land becomes scarce, people destroy forests. True

c) The higher the number of plants, the higher the amount of oxygen in the air. True

d) Wildlife habitat is lost due to deforestation. True

e) If the amount of carbon dioxide gas in the atmosphere increases, the temperature of the atmosphere decreases. False

f) Smoke and dust coming out of the vehicle pollute the environment. True

3. Answer the following questions:

a) Write five negative effects of excessive population growth on the environment. 

👉Any five negative effects of excessive population growth on the environment are as follows:

• Forests are cut down for housing.
• Garbage increases everywhere.
• Air and water become dirty.
• Animals lose their homes.
• There is less land for farming.

b) How does population growth cause air pollution?

👉When more people live in an area, more vehicles and factories are used. They release smoke and dust into the air, causing pollution.

c) Mention the negative impact of population growth on forests in an area.

👉More people need space to live and farm, so trees are cut down. This destroys forests.

d) How does population growth create water scarcity?

👉More people use more water. Water sources dry up if we use too much or do not protect them.

e) What changes occur in the state of air when the number of animals increases and the number of plants decreases? 

👉Animals give out carbon dioxide. Plants take in carbon dioxide and give oxygen. If plants decrease, there is less oxygen and more carbon dioxide in the air.

f) Write how the amount of garbage increases when the operation of industries and factories goes unmanaged.

👉Unmanaged factories throw waste in rivers, land, and air. This creates a lot of garbage and pollutes the environment.

g) Trees have been cut down on the slopes around a village. Due to this, the people there are now facing natural disasters like drying up of water sources, drought and landslides. What can you do to keep the environment clean? 

👉We can plant trees, protect water sources, throw waste in dustbins, and tell others to take care of the environment.