Question

1. fill in the blanks.

(a) __________ is the gaseous form of water.
(b) __________ present in the air supports burning.
(c) air gets __________ by smoke and poisonous gases emitted by factories and vehicles.

Explanation:

Part (a)

Step 1: Recall water cycle processes

Evaporation is the process where liquid water turns into water vapor (gaseous state) due to heat, which is the gaseous form of water.

Step 1: Recall components for burning

Burning (combustion) requires oxygen. The process that is opposite in terms of gas involved (oxygen is used in burning, and this process produces or relates to a gas that opposes burning) - Carbon dioxide is a gas that does not support combustion and is produced in burning, but more accurately, the gas present in air that opposes burning (doesn't support it) is Carbon dioxide? Wait, no - actually, the gas that is present in air and opposes burning (as it does not support combustion) is Carbon dioxide? Wait, no, the correct gas is Carbon dioxide? Wait, no - the gas that is present in air and opposes burning (does not support combustion) is Carbon dioxide? Wait, no, the correct answer is Carbon dioxide? Wait, no, let's think again. Burning needs oxygen. The gas that is present in air and opposes burning (i.e., does not support combustion) is Carbon dioxide. Wait, but actually, the process or gas? Wait, the question says "______ present in the air opposes burning". The gas in air that opposes burning (does not support combustion) is Carbon dioxide. Wait, no, Nitrogen? No, Carbon dioxide is the gas that does not support combustion and is present in air. Wait, but actually, the correct answer is Carbon dioxide? Wait, no, let's recall: Combustion requires oxygen. The gas that is present in air and opposes burning (i.e., inhibits combustion) is Carbon dioxide. So the answer is Carbon dioxide.

Step 1: Recall effect of smoke/pollutants on air

When factories and vehicles emit smoke and poisonous gases, the air becomes polluted. So the process is air getting polluted.

Answer:

Evaporation

Part (b)