"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?
1
The water cycle in wetlands involves surface runoff, subsoil percolation and evaporation.
2
Algae form the nutrient base upon which fish, crustaceans, molluscs, birds, reptiles and mammals thrive.
3
Wetlands play a vital role in maintaining sedimentation balance and soil stabilization.
4
Aquatic plants absorb heavy metals and excess nutrients.