Multiple choice

One of the following gases was absent in the past and came into the atmosphere with the coming of the green plants on earth. Which was that element?

  1. Ammonia

  2. Nitrogen

  3. Carbon dioxide

  4. Oxygen

  5. Carbon monoxide

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Oxygen was absent in the past and came into the atmosphere with the coming of the green plants on earth.