Mendel developed pure lines of peas for his experiments because he wanted them to be

A. control groups
B. fast-growing
O C. more productive
D. the same

i think that d. wind is the answer.   i missed the question when i answered a. currents.

here is the answer

water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering. weathering is the breaking down or dissolving of rocks and minerals on earths surface. once a rock has been broken down, a process called erosion transports the bits of rock and minerals away.