Which layer of soil determines how fertile the soil is?

3 answers

topsoil
how is soil related to bedrock? soil forms from the weathering of bedrock
what is the correct order of the particles that gives texture to the soil from smallest to largest? clay, slit, sand
which phrase best describes soil? unconsolidated material that contains nutreint matter and weathered rock
which layer of soil determines how fertile the soil is? topsoil
its not humus btw