What has led to much of the erosion in the world’s grasslands?
a. wind
c. water
b. acid rain
d. over-grazing

The correct answer is Over grazing.

Grasslands contribute to about 37% of the earth's terrestrial area. Because of over grazing it results in the many problems of soil erosion, many of the world'd important plant are in very condition and show that they are degrading day by day. This over-grazing  of grassland results in loss to global food supply and climate change.