Beautifully illustrated, this book discusses the physics and chemistry. Dorsey, N. Ernest. Most living things need water, food, and air. Some living things consist of a single cell. About two thirds of the weight of cells is accounted for by water, which gives cells many of their properties.
Most food comes from farms either directly as crops or as the animals that eat the crops.
To grow well, plants need enough warmth, light, and water. Crops also must be protected from weeds and pests that can harm them.