“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.
Answer: D
Explanation
Tropical rainforests are often called the “lungs of the planet” because they generally draw in carbon dioxide and breathe out oxygen. Natural wetlands have often been referred to as “earth’s kidneys” because of their high and long-term capacity to filter pollutants from the water that flows through them. Aquatic plants can uptake large amounts of metals from water and/or sediment through active and passive absorption, with this absorption capacity of metals through different organs such as roots, stems, and leaves, making these plants suitable for heavy metal alterations in the aquatic environment.