(a) Plants of the same kind that are grown and cultivated at a place on large scale are referred to as crops. They are mostly grown for useful products.
(b) The first step in crop cultivation is soil preparation which is done to facilitate easy penetration of roots, proper aeration, and growth of soil microbes. Soil preparation includes loosening and turning soil through the process of ploughing.
(c) Selection of healthy seeds is done by putting seeds in a water-filled beaker for some time. The damaged seeds are hollow and lighter in weight and thus float on top of the water. The healthy seeds, being heavier, settle down at the bottom and are used for sowing.
(d) Basic requirements for seed germination and growth of a seedling are sunlight, water, and nutrients. Sowing of seeds to the right depth and proper spacing between seeds and seedlings ensure these requirements are met.