Is a component of soil made entirely of decomposed organic remains. This component increases soil fertility and the ability of soil to retain water. Subsoil increases Humus increases Topsoil decreases?

Humus is the component of soil made entirely of decomposed organic remains. It increases soil fertility and the ability of soil to retain water. Topsoil is the upper layer of soil that contains a mix of organic material and minerals, while subsoil is the layer beneath the topsoil that is less fertile.