"If rainforests and tropical forests are the lungs of the Earth, then surely wetlands function as its kidneys." Which one of the following functions of wetlands best reflects the above statement?
A
The water cycle in wetlands involves surface runoff, subsoil percolation and evaporation.
B
Algae form the nutrient base upon which fish, crustaceans, molluscs, birds, reptiles and mammals thrive.
C
Wetlands play a vital role in maintaining sedimentation balance and soil stabilization.
D
Aquatic plants absorb heavy metals and excess nutrients.
Correct Answer: Option D
Explanation
1. The statement draws an analogy: rainforests/tropical forests are like lungs (gas exchange), and wetlands are like kidneys.
2. The primary function of kidneys in the body is filtration – removing waste products, toxins, and excess nutrients/substances from the blood to produce urine.
3. Option (A) describes the water cycle aspects of wetlands, not their filtering role.
4. Option (B) describes the role of wetlands in supporting biodiversity and food chains, starting with algae.
5. Option (C) highlights the role of wetlands in controlling sedimentation and stabilizing soil.
6. Option (D) states that aquatic plants in wetlands absorb heavy metals and excess nutrients. This purification/filtering function directly mirrors the role of kidneys in removing waste and excess substances.
7. Therefore, option (D) best reflects the analogy of wetlands functioning as the Earth's kidneys.