A.It’s because there are many developing nations.B.It’s because people use too many man-made materials.C.It’s because we have more and more industry.D.It’s because we are building more vehicles.
A.It’s because there are many developing nations.
B.It’s because people use too many man-made materials.
C.It’s because we have more and more industry.
D.It’s because we are building more vehicles.