Multiple choice

The amount of carbon fixed annually by photosynthesis is:

  1. 70 billon tonnes

  2. 80 billon tonnes

  3. 50 billon tonnes

  4. 20 billons tonnes

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

Approximately 70 billion tonnes of carbon is fixed globally through photosynthesis each year, representing the net primary production. This is the total amount of carbon dioxide converted into organic compounds by plants, algae, and cyanobacteria.