Q. 1. The components of air which are harmful to living beings are (a) nitrogen and carbon dioxide (b) dust and water vapour (c) dust and smoke smoke and water vapour.

• Solution:

(c): dust and smoke

Water vapour is important for the water cycle in nature. Nitrogen is necessary for plants.

Carbon dioxide is essential for photosynthesis.

Hence, dust particles and smoke coming out from factories are very harmful for living beings.