Question

Topmost layer of the soil is called……..
A.top soil
B.core
C.silt
D.alluvium.

Answer 1

Hint:Soil may take hundreds to thousands of years for soil to form. If we dig deep down we can see that it is made up of layers. As soil forms, different layers will be created. These layers will differ in size, composition, patterns.

Complete answer:
Soil covers much of the land of Earth and it is made up of mineral-like rock, sand, and silt.

Layers of soil:
I. The top layer of soil which is also called as O layer is made up of Humus and is called as Organic layer.
II. The layer topsoil is found below the O layer and is made up of humus and called the A layer.
III. The third layer is below the A layer and above the B layer and is made up of sand and silt also called the E layer.
IV. The layer is called Subsoil and also the B layer which is found below the E layer and above the C layer and is made up of clay and mineral deposits.
V. The layer below the B layer and above the R layer is called Regolith, it contains broken-up bedrock, and not much organic material is found in this layer.
VI. The unweathered rock material layer is below all the rest layers and called as R layer.

Hence, the correct answer is option (A).

Note:The soil layer can be typically considered into 6 horizons, from the top to the bottom they are O, A, E, B, C, and R. Each horizon has certain features. Also, the particles that make up the soil are classified into - silt, sand, and clay among which sand particles are the largest and clay particles are the smallest.