section_path: Importance to humans/Food
section_name: Food
paragraph_text: Food
  
  Human cultivation of plants is the core of agriculture, which in turn has played a key role in the history of world civilizations. Humans depend on plants for food, either directly or as feed in animal husbandry. Agriculture includes agronomy for arable crops, horticulture for vegetables and fruit, and forestry for timber. About 7,000 species of plant have been used for food, though most of today's food is derived from only 30 species. The major staples include cereals such as rice and wheat, starchy roots and tubers such as cassava and potato, and legumes such as peas and beans. Vegetable oils such as olive oil and palm oil provide lipids, while fruit and vegetables contribute vitamins and minerals to the diet. Coffee, tea, and chocolate are major crops whose caffeine -containing products serve as mild stimulants. The study of plant uses by people is called economic botany or ethnobotany.