Soil erosion occurs
a. where animals eat away all the plants
c. on steep slopes
b. when forests are removed
d. all of the above

Correct D). All of the above

Soil erosion is defined as the movement of the top layer of soil particles by the wind and air. Normally it occurs very slowly but due to human activity like deforestation, overgrazing the rate of soil erosion is increased by many folds.

Due to soil erosion, the top fertile layer of soil is removed that results in low productivity and loss of vegetation too. It can also lead to floods and mudslides.

Hence, the correct answer would be option D

digestion

it excretes wastes