Question 1

Which gas is primarily responsible for the greenhouse effect leading to global warming?

Accepted Answer

Carbon dioxide. Carbon dioxide traps heat in the atmosphere, creating a warming effect on the planet. It is primarily released through the burning of fossil fuels and deforestation activities. This process is generally recognized as the leading cause of climate change.

Question 2

What is the primary indicator used to measure the level of organic pollution in a water body?

Accepted Answer

Biochemical Oxygen Demand (BOD). BOD measures the amount of oxygen consumed by bacteria while decomposing organic matter under aerobic conditions. A high BOD value indicates that the water is heavily contaminated with organic waste. It is a fundamental parameter for assessing the health of aquatic ecosystems.

Question 3

Which pollutant is the main cause of 'Minamata disease' in humans?

Accepted Answer

Mercury. Minamata disease is a neurological syndrome caused by severe mercury poisoning. It first occurred in Japan due to the release of methylmercury into industrial wastewater. This toxic metal accumulates in fish, which then enters the human food chain.

Question 4

What is the phenomenon called when excessive nutrients in water bodies lead to overgrowth of algae?

Accepted Answer

Eutrophication. Eutrophication is caused by the runoff of fertilizers and detergents containing phosphorus and nitrogen. This nutrient enrichment triggers rapid algal blooms that deplete dissolved oxygen in the water. It often results in the death of fish and other aquatic organisms.

Question 5

Which layer of the atmosphere contains the ozone layer that protects Earth from ultraviolet rays?

Accepted Answer

Stratosphere. The stratosphere houses the ozone layer, which filters out harmful UV radiation from the sun. Human activities like the use of chlorofluorocarbons (CFCs) can lead to the depletion of this protective shield. Damage to this layer is generally linked to increased risks of skin cancer and cataracts.

Air & Water Pollution — Set 1