The work of food-production as a process of nature is. progressive, but moves ever in an interworking cycle that conserves all products of living as well as constructs all used for food. In general function in nature bacteria decompose, plants construct, animals transform. Human beings give off carbon dioxid that plants use and nitrogenous waste that bacteria use. But in these nothing new is contributed, as they are also the products of living of all animal life.

The part humanity uniquely performs in food-production is mainly mental in the practical and scientific conduct of living. Human work enters into food-cultivation, care, selection, preparation for humankind, animals, plants, bacteria. Because of humanity's greater physical dexterity and elasticity in developing new powers, it is humanity that learns how nature interworks and can be worked together so as to advance race-life and extend natural resources and their utilization.

The foods of bacteria, plants, animals, humankind, which in themselves differ, contain the same chemical elements variously combined and in varying quantities. The chief of these are nitrogen, carbon, oxygen, hydrogen. There are many others of great importance too, though used in much smaller amounts. Such are calcium, sodium, potassium, sulphur, phosphorus. What these do as substances alone is different from what they do when combined. Different combinations also act differently. How these elements are brought together determines the constitution of the foods or organisms they compose. Air, sunlight, soil, water, have part in effecting these combinations. Plants need sunlight to get carbon from carbon dioxid; bacteria leave the nitrogen compounds in the soil; plants find them there; water aids in the transfusion of food as food is being transformed for assimilation in the body.

Food-Cycle Bacteria - Plants - Animals - Humankind

Carbon passes through the atmosphere to plants; nitrogen (generally) through the soil. Oxygen unites with food in chemical action from which heat evolves. This is the source of body-energy and heat. Find on diagram below as many of above facts as possible.