Environmental Issues

Explain how an electrostatic precipitator and a scrubber work to control air pollution from industries. What role does a catalytic converter play in reducing vehicular pollution?

What is the greenhouse effect? Name any two greenhouse gases and state one consequence of global warming.

What is eutrophication? Explain how it leads to the death of aquatic life in a water body.

Describe the case study of (i) the reduction of vehicular pollution in Delhi (CNG) and (ii) the joint forest management/Chipko movement, explaining the lessons learnt from each.

How is ozone depleted in the stratosphere by CFCs? What is the effect of increased UV-B radiation on humans? Name the international treaty that controls ozone-depleting substances.

What is biomagnification? Explain it with reference to DDT in an aquatic food chain.

Differentiate between biodegradable and non-biodegradable wastes, giving two examples of each. What is the significance of segregating waste for effective management?

State one harmful effect of noise pollution on human health.

How many marks is Environmental Issues worth in the Class 12 board exam?

Around 4 marks of the 70-mark CBSE Biology theory paper, based on the official unit-wise weightage. Pollution types + case studies — quick scoring.

Is Environmental Issues easy or hard?

It's rated easy — one of the easier chapters in Class 12 Biology. Most students need about 2 hours to cover it well.

What should I focus on in Environmental Issues?

Going by the board papers themselves, the recurring areas are Air Pollution Control, Greenhouse Effect, Eutrophication, Case Studies, Ozone Depletion — that's where the marks actually sit.

What questions come from Environmental Issues in board exams?

Between 2019–2024, CBSE board papers asked questions from this chapter on Air Pollution Control, Greenhouse Effect, Eutrophication, Case Studies — 1- to 5-mark questions.