Q.Which of the following region has maximum biodiversity?

Step 1. Compare the tree-species counts the chapter gives for each biome type. The Tundra and Taiga of northern Canada, Alaska, northern Europe and Russia support fewer than 12 tree species in total — ruling out (a) Taiga as the answer.

Step 2. Temperate forests, such as those of the United States, hold 20-35 tree species — richer than Taiga but still far below tropical levels, ruling out (c) Temperate rain forest.

Step 3. Mangroves (d) are ecologically vital coastal wetland forests, but they occupy a narrow, specialised saline-intertidal niche that naturally supports a smaller overall species pool than a full tropical forest system.

Step 4. Tropical forests, exemplified by Panama's forests with over 110 tree species in a comparatively small area, sit at the peak of the latitudinal diversity gradient — the chapter's central pattern that biodiversity rises from the poles toward the equator, driven by warm, stable, resource-rich tropical conditions.

Compare each biome's tree-species richness figures given in the chapter and apply the latitudinal-gradient rule that diversity peaks in the tropics.

• Picking mangroves for their ecological importance without checking that their species pool is narrower than a full tropical forest's.
• Confusing 'rain forest' in option (c) with tropical rain forest, when the option specifically names temperate rain forest.