CG SCERT Chhattisgarh State Board Class 7 Science & Technology Chapter 1 Life on Earth Exercises Questions and Answers.
(1.) Fill in the blanks
(a.) Compared to a country there is more _____ found in the earth’s environment.
Ans. Organisms.
(b.) In comparison to a normal environment _____ organisms are found in desert and
cold regions.
Ans. different.
(c.) Many long ______ are found in oceans.
Ans. food chain.
(d.) Some animals don’t have to drink water because they get sufficient water from _____
ans. food.
(1.) Fill in the blanks
(a.) The three essential requirements of life are – _____ , ______ and _______
ans. Food, air and water.
(b.) In deserts, days are very ______ and nights are very ______
Ans. hot, cold.
(c.) Living organisms are linked to each other through _______
Ans. food chains.
(d.) The place where living organisms live and reproduce is called ______
ans. their habitat.
(e.) Due to ______ living organisms live in their habitat without any difficulty.
Ans. different.
(2.) True / False:
(a.) There is water all around in a desert.
Ans. False
In the desert the water is scarcely.
(b.) Sea plants respire by taking oxygen from the air.
Ans. False.
Sea plants respire by taking oxygen from the air dissolved in water.
(c.) Major carnivorous animals of Arctic region are rats, deer and rabbit.
Ans. False.
Rats, deer and rabbit are the main herbivores animals found in Arctic region.
(d.) Animals living in the Arctic region have hair on their body.
Ans. True.
(e.) Organisms living in Arctic or desert region can live in our habitat.
ans. False
Organisms living in Arctic or desert region cannot live in our habitat.
(3.) Answer these –
(a.) Why don’t we see lizards and weevil(ghun) drink water?
Ans. Lizards and weevil are not seen drinking water because they get sufficient water from the food they eat and thus do not need to drink water.
(b.) Where does the tree growing from a wall get water and minerals from?
Ans. The tree is growing from a wall get water and minerals from moisture of wall.
(c.) Why are most of the animals found in arctic region white in colour?
Ans. Most of the animals are found in arcticregion white in colour because the region is so cold that it is covered with a thick coat of snow almost all the year around.
(d.) Think of and write a food chain which starts in the ocean but ends on earth.
Ans. Ocean plants and algae -> small animals -> big animals and small fish -> big fish -> seal -> polar bear.
(e.) Make a food chain each for the desert and for the ocean.
ans. Plants -> desert insects -> lizards and rats -> hawk and owl
Ocean plants and algae -> small animals -> big animals and small fish -> big fish -> seal -> polar bear.
(f.) Living organisms get modified according to the environment in which they live. If the environment on the earth became the same everywhere, how would be the living organisms effected? Write in your own words.
ans. If the environment on the earth became the same everyone then the organisms are increasing. Food chains are spread in various condition. Then the eco-system gets dis-balance.
(h.) How would polar bears be effected if all the algae on the surface of the oceans disappear?
Ans. If all the algae on the surface of the oceans disappear then there are no fish, no seals for food. That is because polar bears are effected in this situation.