Question

(a) State the way by which oxygen enters in the atmosphere.

(b) State the ways by which oxygen is removed from the atmosphere.

(c) How does the percentage of oxygen in the atmosphere remain constant, inspite of the fact that a large amount of it is used for combustion and respiration.

Answer 1

(a)The way by which oxygen enters the atmosphere:

• Plants are the greatest source of oxygen in the atmosphere.
• Plants use sunlight and carbon dioxide to produce oxygen through the process of photosynthesis.
• The oxygen from plants enters the atmosphere.

(b) The ways by which oxygen is removed from the atmosphere are:

1. By burning fossil fuels

2. By cutting trees.

3. By Respiration and decay mechanism

(c) The green plants who are capable of photosynthesis are taking up CO₂ and producing O₂ in exchange, Amazon forests are said to be responsible for 20% of the World’s oxygen and these are also called the lungs of the earth.