Crop rotation is a method of soil conservation because
a. the land produces more than one type of crop
b. it requires plowing and tilling that reduces soil compaction
c. it does not use the same parcel of land in sequential
seasons
d. it avoids the depletion of soil nutrients

Crop rotation is a method of soil conservation because  it avoids the depletion of soil nutrients.

It is the practice of growing a series of different types of crops in the same area in sequenced seasons. Crop rotation helps in reducing soil erosion and increases soil fertility and crop yield.

Growing the same crop in the same place for consecutive (many) years in a row disproportionately depletes or consumes the soil of certain nutrients.

Biochemistry, it deals with the chemical constitution, the breakdown and the synthesis of plant and animal products.