The richest layer of soil would be found at Horizon 0
Horizon A
Horizon B
Horizon C
Bedrock

The first horizon is the “A“ horizon. It is more commonly called the topsoil. The topsoil is usually the darkest layer of the soil. It is the layer with the most organic material.

Explanation:

hi~~

i would say that hybridization occurs frequently in nature, because there are many types of hybrids that have occurred naturally, such as the mule (male donkey + female horse)