Which of the following statements best describes "carbon fertilization"?

Answer: (a) Increased plant growth due to increased concentration of carbon dioxide in the atmosphere.

Carbon fertilisation = faster photosynthesis and growth as CO₂ rises (strongest in C₃ plants).

The idea

Carbon dioxide is the raw material of photosynthesis. With more of it in the air, many plants make food faster. They can also keep their leaf pores partly closed and so lose less water. The result is extra growth, called carbon fertilisation.

More CO₂ in the air → Faster photosynthesis → Leaf pores open less → less water lost → More plant growth → But limited by nitrogen, water and heat

Why the others are wrong

(b) That is global warming.

(c) That is ocean acidification.

The trap

All four are real effects of CO₂ — only (a) is called “fertilisation”.

Elimination technique

Option (d) speaks of “all living beings on Earth”. Absolute words usually mark the wrong option in Environment PYQs.

Also know

The gain is larger in C₃ plants (rice, wheat, most trees) than in C₄ plants (maize, sugarcane, sorghum), which already concentrate CO₂ inside the leaf. There is a cost: grain grown under high CO₂ has less protein, zinc and iron. Satellites have recorded a “greening” of the Earth partly due to this effect, and it is one reason land still absorbs part of our emissions.