Question

The layer which has slightly weathered rock and no humus content is​

Answer 1

Explanation:

The O Horizon is composed of humus (organic matter),

the A Horizon is a mixture of minerals and organic matter,

the B Horizon is composed mainly of minerals and the D horizon is solid bedrock.

Hope it helps...

Answer 2

Answer:

A soil horizon is a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath. Horizons are defined in many cases by obvious physical features, mainly colour and texture. These may be described both in absolute terms (particle size distribution for texture, for instance) and in terms relative to the surrounding material, i.e. ‘coarser’ or ‘sandier’ than the horizons above and ....