Soy varies in growth, habit, and height. It may grow not higher than 20 cm (7.8 inches), or grow up to 2 meters (6.5 feet) high.

Soybeans occur in various sizes, and in many hull or seed coat colors, including black, brown, blue, yellow, green and mottled. The hull of the mature bean is hard, water resistant, and protects the cotyledon and hypocotyl (or "germ") from damage. If the seed coat is cracked, the seed will not germinate. The scar, visible on the seed coat, is called the hilum (colors include black, brown, buff, gray and yellow) and at one end of the hilum is the micropyle, or small opening in the seed coat which can allow the absorption of water for sprouting.

Oil and protein content account for about 60% of dry soybeans by weight.

Nutrition
For human consumption, soybeans must be cooked with "wet" heat in order to destroy the trypsin inhibitors (serine protease inhibitors). It is not advisable to eat raw soybeans.

Soybeans are considered by many agencies to be a source of complete protein.[9] A complete protein is one that contains significant amounts of all the essential amino acids that must be provided to the human body because of the body's inability to synthesize them. For this reason, soy is a good source of protein, amongst many others, for vegetarians and vegans or for people who want to reduce the amount of meat they eat. According to the US Food and Drug Administration:

Soy protein products can be good substitutes for animal products because, unlike some other beans, soy offers a 'complete' protein profile. ... Soy protein products can replace animal-based foods—which also have complete proteins but tend to contain more fat, especially saturated fat—without requiring major adjustments elsewhere in the diet.

Soybeans are an important global crop, providing oil and protein. In the United States, the bulk of the crop has its oil solvent-extracted with hexane, then the "toasted" defatted soymeal (50% protein) makes possible the raising of farm animals (eg. chicken, hog, turkey) on an industrial scale never before seen in human history. A very small proportion of the crop is consumed directly by humans. Soybean products do appear in a large variety of processed foods.