Which of the following strongly threatens biodiversity?

Answer: (c) Destruction of natural habitats and vegetation and shifting cultivation

Habitat destruction is the No. 1 driver of biodiversity loss; slash-and-burn shifting cultivation clears forest again and again.

The idea

A species can survive hunting or pollution if its home remains. It cannot survive the loss of the home itself. That is why destruction of habitat is the largest single cause of biodiversity loss.

Shifting cultivation: a forest patch is cut and burnt → Crops are grown for two or three years → The farmer moves on; the patch is left to regrow → Earlier: 15–20 years of rest → forest recovered → Now: rest of only a few years → forest does not return

Why the others are wrong

(a) Mangroves and wetlands are fragile — but they are what is threatened, not what threatens.

(b) Inaccessible places are safer: fewer people, less disturbance.

(d) Biosphere reserves are a conservation tool.

The trap

(a) mixes up a vulnerable ecosystem with a threat to it.

Also know

Shifting cultivation has many names: jhum in North-East India, podu in Andhra Pradesh and Odisha, milpa in Mexico, ladang in Indonesia. It was sustainable when populations were small.