In the outline find your section on soil horizons in it you will find a diagram representing a view of a soil cut away which of the layers in this example represents the horizon that is very thin and contains large amounts of organic matter

A. O
B. A
C. B
D. C

A Layer

Explanation:

There are mainly 5 layers of soil- O, A, B, C and R. These layers are called horizons. Each layer/horizon has its own characteristics. Each layers features differentiate them from the other layers. Lets take a view at these 5 layers of soil:

O - Organic soil materials

A - Mineral; organic matter (humus) accumulation

B - Subsurface accumulation of clay (consists of different tyoes of minerals)

C - Little or no pedogenic alteration, unconsolidated earthy material, soft bedrock

R - Bedrock (strongly cemented layer of soil)

distance = 150m

displ = root (50 ^2 + 100^2)

root(2500+10000)

root 125000