Answer: Nitrogen.
- A Calcium
- B Phosphorus
- C Nitrogen
- D Potassium
Correct answer: C. Nitrogen
Explanation: Insectivorous plants (Venus flytrap, Drosera, Nepenthes) grow in nitrogen-poor soils (bogs, wet rocks). They trap insects to supplement their nitrogen supply. This is an adaptation to low-nutrient environments.
Atmospheric N₂ is fixed into ammonia by nitrogen-fixing bacteria (protected from oxygen by leghaemoglobin in root nodules), converted to nitrate via nitrification for plant uptake, and eventually returned to the atmosphere as N₂ via denitrification, completing the cycle.
Concept context
Essential mineral elements, their roles and deficiency symptoms. Nitrogen fixation and soil nutrition.