Among types of research, only can establish causality.
a. random surveys
b. experiments
c. representative surveys
d. biased studies

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.