A farmer and a housewife may have never studied biology, yet both of them know some of its general principles through experience. State any two principles which they know.

A farmer, although has never studied biology, knows by his experience how to increase his produce. He knows how to plough and plant crops and select good quality seeds for sowing. Right from selecting germfree seeds to sow, act of ploughing, crop plantation, using fertilizers, irrigation and its types, crop harvesting, cross-breeding with other plants, weed removal, etc, they have knowledge of basic biological concepts.

A housewife, by using her experience knows which fruit or vegetable to grow and how much time. She knows all the nutritional values of various foodstuffs. She can suggest first hand treatment for simple cold, cough and other mild mishaps. She knows to tame some useful animals like cow, goat and dog for her maximum benefit.