Answer: O horizon
Step-by-step explanation:
A soil horizon can be define as a layer of soil that lies parallel to the surface of earth. Each soil horizon varies on the basis of physical, biological and chemical characteristics. The soil horizon varies on the basis of color, texture, composition.
O horizon is the soil horizon which lies at the top layers or sublayers of the soil surface. It accumulates the large amount of organic matter this is because of the fact that it accumulates the mass of dead and decaying matter of plants and animals. The degradation of this dead matter results in the formation of organic matter. This layer is suitable for plant growth.