Question

a geologist is studying a new soil profile. in analyzing the profile, she finds that the topsoil is rich in organic material. she concludes that this soil would be great for growing crops. what materials combined to form the topsoil? weathered bedrock and wind - blown sand decomposed humus and wind - blown sand decomposed plant litter and weathered parent material deposited sediment and decomposed plant litter

Explanation:

Topsoil is formed from decomposed plant litter (organic matter) and weathered parent material (inorganic part). Weathered bedrock alone (without organic matter) is less fertile. Decomposed humus is part of organic matter but wind - blown sand is not a typical main component. Deposited sediment is more related to soil formation in some specific environments (like floodplains) but the combination of decomposed plant litter (organic) and weathered parent material (inorganic) is the classic composition for fertile topsoil.

Answer:

decomposed plant litter and weathered parent material