Multiple choice

Which one does not contribute to the reproduction of CO2?

  1. Respiration

  2. Decomposition of organic wastes

  3. Burning of fossil fuels

  4. Birds excreta

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

Some amount of phosphorus is returned to the earth, in the form of bird's excreta - Guano deposits (excreta of marine birds) and dead fish (around 60,000 tonnes which is less than 0.5% of phosphorus discharged from rivers)