a) Coniferous forest

 b) Dry deciduous forest

 c) Mangrove forest 

d) Tropical rainforest 

8. Ans: d 

Explanation:

Tropical rainforests appear like a thick canopy of foliage, broken only where it is crossed by large rivers or cleared for cultivation. All plants struggle upwards for sunlight resulting in a peculiar layer arrangement. The taller trees, smaller trees form the next layer, and the ground is rooted with ferns and herbaceous plants which can tolerate shade. 

Almost all the action in a rainforest (not just photosynthesis but also flowering, fruiting, predation and herbivory) happens high in the canopy. Apart from the trees, the vegetation is largely composed of plant forms that reach up into the canopy vicariously, by climbing the trees (vines and lianas, including many species and fig) or growing as epiphytes, which are plants that grow on other plants, rooted on the damp upper branches. 

There is intense biological activity in the soil of tropical rainforests. Leaf litter decomposes faster than in any other biome, and as a result the soil surface is often almost bare. The mineral nutrients in fallen leaves are rapidly released, and, as rainfall seeps down the soil profile, nutrients may be carried well below the levels at which roots can recover them. Almost all the mineral nutrients in a rain forest are held in the plants themselves, where they are safe from leaching, when such forests are cleared for agriculture or timber is felled or destroyed by fire, the nutrients are released and leached or washed away.

Hence, option d is correct. 

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