A．Too many animals eating the plants ill one small area.
B．Planting too much vegetation in one small area.
C．Too many people building houses in one small area.
D．Bringing together the wrong kinds of animals and plants.

A.Too
B.
B．Planting
C.
C．Too
D.
D．Bringing

【参考答案】

A
解析：What?is?over?grazing?