The Environment and Us - Standard 5 - Environmental Studies - Part 1 - Balbharati
The Environment and Us
Exercise
Q. 1 What’s the solution?
Rivers and lakes are filled with water hyacinth.
Ans. 1. Use boats or specialized machinery to remove water hyacinth from affected areas.
2. Introduce animals that feed on water hyacinth to control its growth.
3. Use minimum chemicals or herbicides.
4. Engage local people in the removal of water hyacinth.
5. Teach people about the problems caused by water hyacinth and encourage them to do things that stop it from spreading.
Q. 2 Use your brain power !
What would happen if no kites (birds) are left in a particular region? Which living things would increase in number? Which would decrease?
Ans. 1. If no kites (birds) are left in a particular region then the ecosystem could become imbalanced.
2. Animals like rabbits, squirrels and birds that kites usually eat would likely increase in number.
3. Pests that are eaten by kites, scavengers that depend on kites for the flesh of dead bodies and other predators that might face less competition from kites could decrease in number.
Q. 3 Answer the following questions.
(a) What is meant by migration?
Ans. The movement of people or animals from one place to another is called migration.
(b) Describe the life-cycle of birds.
Ans. Birds begin as eggs in nests, hatch into chicks, grow feathers, and learn to fly. As they grow, they become independent, building nests, laying eggs, and repeating the life cycle.
(c) Give two causes of air pollution.
Ans. 1. tremendous quantities of carbon dioxide enter the air due to burning of fuels.
2. When fuels are burnt in vehicles, they give out certain poisonous gases as well as smoke.
3. Industries also let out some poisonous gases into the air. This leads to air pollution on a very large scale.
(d) For what purpose do we use land obtained by clearing forests ?
Ans. We use cleared forest land for constructing roads, railways, buildings, bridges, farming, and dams.
Q. 4 Give reasons.
(a) It is important to conserve the living components of the environment.
Ans. If the different types of plants and animals become extinct one by one, many of the links in the different food chains will be lost. This will affect the entire living world on the earth and the balance in nature will collapse. That's why, it is important to conserve the living components of the environment.
(b) The numbers of wild animals are falling day by day.
Ans. Wild animals live and find food in the forests. But forests are getting smaller. Due to this, animals lose their homes and their food. Therefore, the numbers of wild animals are falling day by day.
Q. 5 True or false ?
(a) Dead plants and animals are abiotic components.
Ans. False.
(b) It is necessary to conserve biodiversity.
Ans. True.
6. Classify the following as natural or man-made.
Soil, horse, stone, water hyacinth, book, sunlight, dolphin, pen, chair, water, cottonwool, table, trees, brick.
| Natural | Man-made |
|---|---|
| soil | book |
| horse | pen |
| stone | chair |
| water hyacinth | table |
| sunlight | brick |
| dolphin | |
| water | |
| cottonwool | |
| trees |
