Which of the following biomes likely has the thinnest layer of topsoil a. tropical rainforest b. deciduous forest c. grassland d. desert

The answer is Desert.  The biomes that likely has the thinnest layer of topsoil is the Desert. The topsoil is a very important layer of soil because on this layer of soil, plants are nourished. The topsoil have to be healthy to grow plants on it. It contains humus, bacteria, fungi, insects and worms. But you can hardly find these in the Desert.