Which type of soil is most suitable for plant growth?

Minerals of soil are derived from

State the utilities of the land.

The $O$ soil layer is rich in:

Select the correct statements regarding the role of soil:
$(I)$ Soil is a reservoir of essential elements.
$(II)$ Soil not only supplies minerals but also harbours nitrogen-fixing bacteria.
$(III)$ Soil acts as a matrix.
$(IV)$ Soil holds water and supplies air to the roots.

Which one is the main source of minerals essential for man and other organisms?