Question

A. Tick () the correct answer.
1. Two main gases present in atmosphere are:
a. oxygen and argon b. nitrogen and oxygen
2. Meteoroids burn up in: a. troposphere b. exosphere c. mesosphere
3. Atmosphere consists of 78 per cent of a nitrogen b. argon
4. Distillation involves: a. evaporation b. condensation c. both a and b
5. During purification of water in waterworks department, germs are killed in this
step: a. chlorination b. sedimentation
6. The amount of water vapour in the air is called: a. gases b. humidity
7. This gas is colourless and odourless: a. argon b. chlorine
8. Hot air: a. rises up b. moves down
B. Fill in the blanks with the correct option.
17. The layer of atmosphere in which we live in, is the ........
(stratosphere/troposphere)
..... is an important plant nutrient. (Nitrogen/Oxygen)
3. The layer of air surrounding the Earth is called ..
(troposphere/atmosphere)
4. When there is more rainfall, the water table gets ...
(higher/lower)
5. Purifying water by passing through a filter paper is called
(distillation/filtration)​

Answer 1

Answer:

1- b

2- c

3- none of them as it contains 78 percent of oxygen.

4- c

5- a

6- b

7- a

8- a

B.

1- troposphere

2- nitrogen

3- atmosphere

4- higher

5- filtration

Explanation: