Biology ICSE Class 6 Important Questions Chapter 8 Our Environment
Extra Questions
Question 1.
What conditions on the Earth make it a living Planet?
Answer:
a. Optimum distance from the sun.
b. Presence of oxygen, carbon-dioxide, nitrogen and other gases.
c. Presence of water.
d. Gravitational force.
e. Presence of minerals.
Question 2.
What are the various layers of the earth ?
Answer:
Earth is made up of three layers :
a. Outermost solid layer called crust.
b. Layer of molten rocks called mantle.
c. Innermost layer is core which is separated into a liquid outer core and a solid inner core.
Question 3.
Name three spheres of the earth.
Answer:
a. Lithosphere (layer of soil amd rocks)
b. Hydrosphere (layer of water)
c. Atmosphere (layer of gases).
Question 4.
Name three components of the environment.
Answer:
a. Biotic component (all living organisms)
b. Abiotic component (air, water, soil etc.)
c. Cultural component.
Question 5.
What are scavengers ?
Answer:
The living organisms which eat dead and decaying matter are called scavengers, e.g. Vultures.
Question 6.
Name two harmful gases released by air pollution.
Answer:
Carbon-monoxide, sulphur-dioxide.
Question 7.
Name two animals that lead a noctural (active at night) life.
Answer:
Cockroaches, termites.
Question 8.
What is the difference between hibernation and aestivation.
Answer:
Hibernation : Some animals remain underground and sleep throughout winter. This is called hibernation, e.g. Lizards, snakes.
Aestivation: Some animals (desert) sleep throughout summer. This is called aestivation, e.g. Snakes, rates.
Question 9.
What is apiculture ?
Answer:
The management of honeybees for commercial purposes is called apiculture.
Question 10.
What are autotrophs, heterotrophs and scavengers ? Answer briefly.
Answer:
Autotrophs : The living organisms i.e.; plants which can pre¬pare their own food are called autotrophs.
Heterotrophs : Living organisms which cannot prepare their own food but consume their needs from other sources are called heterotrophs.
Example : Cow, dog, man.
Scavengers : The living organisms which eat dead and decaying matter are called scavengers.
Example : Vultures feed on dead cow or deer.
Question 11.
What is an environment ? What is meant by environ¬mental pollution ?
Answer:
All that surrounds and affects the life of an organism (plant or animal) is its environment.
Environmental pollution: It is the addition of any harmful or * unwanted substance to the environment which adversely alters the natural quality of environment.
Question 12.
Name two harmful gases released into the air by factories, motor vehicles, etc. What are the two effects of air
pollution on humans ?
Answer:
The two harmful gases released into the air by factories etc are:
(a) Sulphur-di-oxide
(b) Carbon monoxide.
Effects of air pollution on humans :
(i) Can cause respiratory diseases like lung cancer.
(ii) May lead to death if inhaled in large quantities like CO causes poisoning.
Question 13.
Why is coal called a fossil fuel ? Why is it considered a non-renewable source of energy ?
Answer:
Coal is formed from vegetable matter buried under earth in the distant past. The vegetable matter got converted into coal due to high pressure and high temperature and thus coal is known
as fossil fuel.
Coal is considered as non-renewable source of energy as it would take millions of years to be produced again.
Question 14.
List any five products which are obtained by distillation of crude petroleum.
Answer:
The five products which are obtained by the distillation of cmde petroleum are:
(a) Petroleum gas
(b) Kerosene
(c) Diesel
(d) Lubricating oil
(e) Paraffin wax.
Question 15.
What is a food web ? Give an example.
Answer:
Interconnected food chains form a food-web.
ICSE Class 6 Biology Important Questions