"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
Explanation
The correct answer is D, Aquatic plants absorb heavy metals and excess nutrients. Kidneys filter waste from the blood, and wetlands likewise filter pollutants out of the water that passes through them.
As water flows slowly through a wetland, plants such as reeds, cattails and water hyacinth, along with microbes in the mud, take up nitrogen, phosphorus and heavy metals and trap fine particles. This purifies the water before it reaches rivers, lakes or groundwater, which is why wetlands are often called "the kidneys of the landscape". The East Kolkata Wetlands, a Ramsar site, treat much of Kolkata's sewage naturally and use it for fish farming and vegetable growing.
A is wrong because it simply describes the water cycle, not a cleaning role. B is wrong because it describes wetlands as a food base for wildlife, which matches their richness, not the kidney function. C is wrong because controlling sediment and stabilising soil is about erosion, not filtering out pollutants.
Exam tip: Forests = lungs of the Earth; wetlands = kidneys (filtering); East Kolkata Wetlands = natural sewage treatment.
Practice Questions
View allWhat is 'Climate Neutral Now' initiative?
1. It encourages organizations and other interested stakeholders to act now in order to achieve a carbon neutral world by 2030.
2. It derives its aims from the Paris Agreement.
Select the correct answer using the code given below :
- A.1 only
- B.2 only
- C.Both 1 and 2
- D.Neither 1 nor 2
Show answer
Climate Neutral Now takes its aim from the Paris Agreement, but the target it works towards is a climate-neutral world by the middle of the century, not by 2030.
Read the full explanation →Which of the following statements is/are correct about 'Action for Climate Empowerment' (ACE)?
1. It is a term adopted by the UN Framework Convention on Climate Change.
2. This term is related to the Paris Agreement.
Select the correct answer using the code given below:
- A.1 only
- B.2 only
- C.Both 1 and 2
- D.Neither 1 nor 2
Show answer
Action for Climate Empowerment is the UNFCCC's own name for its work on climate education and public awareness, and it covers the Paris Agreement too.
Read the full explanation →Which one of the following is NOT correct about organic farming?
- A.It does not use genetically modified seeds
- B.Synthetic pesticides or fertilizers are not used
- C.It uses minimal crop rotation
- D.It uses ecologically protective practices
Show answer
Organic farming relies heavily on crop rotation, not on as little of it as possible, so this is the statement that is not correct.
Read the full explanation →Consider the following statements :
1. Agricultural soils release nitrogen oxides into environment.
2. Cattle release ammonia into environment.
3. Poultry industry releases reactive nitrogen compounds into environment.
Which of the statements given above is/are correct?
- A.1 and 3 only
- B.2 and 3 only
- C.2 only
- D.1, 2 and 3
Show answer
Fertilised soils, cattle and poultry are all major sources of reactive nitrogen in the environment. Reactive nitrogen means nitrogen in forms other than the inert N₂ gas of the air, such as ammonia, nitrogen oxides, nitrous oxide and nitrate.
Read the full explanation →What is/are unique about 'Kharai camel', a breed found in India?
1. It is capable of swimming up to three kilometres in seawater.
2. It survives by grazing on mangroves.
3. It lives in the wild and cannot be domesticated.
Select the correct answer using the code given below.
- A.1 and 2 only
- B.3 only
- C.1 and 3 only
- D.1, 2 and 3
Show answer
The Kharai camel of Kutch in Gujarat can swim through seawater to reach mangrove islands, where it feeds on mangrove leaves.
Read the full explanation →