Question

Assertion (A): Oxygen is essential for all aerobic forms of life.

Reason (R): Free oxygen atoms combine with molecular oxygen to form ozone.

Options

• Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).

• Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

• Assertion (A) is true, but Reason (R) is false.

• Assertion (A) is false, but Reason (R) is true.

Answer 1

Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).

Explanation:

"Oxygen is essential for all aerobic forms of life."

• True.

• Aerobic organisms use oxygen for cellular respiration to release energy from food. Without oxygen, aerobic life cannot survive.

"Free oxygen atoms combine with molecular oxygen to form ozone."

• True.

• In the upper atmosphere (stratosphere), free oxygen atoms (O) produced by UV radiation react with molecular oxygen (O₂) to form ozone (O₃): O + O₂​→O₃​