A student compared the chemical composition of soil in a certain area with the bed rock beneath it. She found that the chemical compositions were different. Which statement would best explain the difference in chemical composition? A. the soil layers were mature because a large amount of time had passed.

B. the soil is all that is left of a different kind of rock that weathered away.

C. The areas rain and extreme temperatures caused the soil to develop

D. the rainwater washed iron oxide from the A to the D horizon.