Page 157 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

G. Long-answer question.

1. Life would be impossible without plants. Explain.
Ans: Life would be impossible without plants for the following reasons :

• Plants produce oxygen through photosynthesis, which is essential for all living
beings.

• Plants are the foundation of the food chain, providing nutrients.
• Plants absorb carbon dioxide, helping to regulate atmospheric levels.

• They provide habitats & shelter for countless species of life forms.
• Many medicines are derived from plants.

• They influence weather patterns & help maintain the balance of natural cycles.
• Plants contribute to water purification & soil fertility.

2. What happens when an animal dies in a forest?
Ans: When an animal dies in a forest, animals like vultures & insects first eat it, breaking

sown it into smaller pieces. Then, decomposers such as bacteria & fungi break down
the remaining material into nutrients. These nutrients enrich the soil, helping the

plants to grow.
3. How are plants and animals dependent on each other?

Ans: Dependence of Animals on Plants
• For food: Plants synthesise their own food with the help of sunlight, water and

carbon dioxide by photosynthesis.
• For shelter: Trees provide shelter to many animals, such as monkeys, squirrels,

koalas etc. Trees also provide home to a large variety of birds. All living things
take shelter from rain and harsh sunlight under trees.

Dependence of Plants on Animals
• For carbon dioxide: Plants need carbon dioxide from the atmosphere for

photosynthesis. Animals and human beings breathe out carbon dioxide during
respiration, which is taken in by the plants for photosynthesis.

For nutrients: The dead remains of animals are broken down by the decomposers
into simpler forms which enrich the soil with several nutrients. Plants take in

these nutrients from the soil.
For pollination: Pollination is an essential process for the plants to reproduce

sexually. Insects and birds feed on the nectar of flowers. This helps in the process
of pollination and reproduction in plants.

• For dispersal of seeds: Some plants have sticky or barbed seeds, or fruits, that
stick to the feathers or fur of mobile animals. Some seeds are explosi vely

released over short distances whereas others fall to the ground at the base of

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