The correct answers are as follows:
1. D.
Earthworm is not a major component of the soil. The major components of the soil refers to those materials which combine together to form soil. Examples of components of the soil are water, air, humus, etc. An earthworm is an animal which live inside the soil; it helps the soil by promoting the aeration of the soil.
2. D.
The particles that made up a soil determine the soil texture of that soil. Soill texture refers to the relative contents of the particles of various sizes which are find in a particular soil. Soil texture affect the amount of water a soil can hold and the ease with which the soil can be worked.
3. B.
The main source of organic matter in the soil is plant. Dead plants fall down to the ground and are worked upon by microbes which decompose them and turn them to humus. Humus is the major organic content of the soil and the fertility level of a soil depends on the amount of humus it contains.
