Food is any substance consumed to provide nutritional support for the body. It is usually of plant or animal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ingested by an organism and assimilated by the organism's cells in an effort to produce energy, maintain life, or stimulate growth.
Historically, people secured food through two methods: hunting and gathering, and agriculture. Today, most of the food energy consumed by the world population is supplied by the food industry.
Worldwide more human beings gain their livelihood from agriculture than any other endeavor; the majority are self-employed subsistence farmers living in the tropics]citation needed[. While growing food for local consumption is the core of tropical agriculture, cash crops (normally crops grown for export) are also included in the definition.
When people discuss the tropics, it is normal to use generalized labels to group together similar tropical areas. Common terms would include the humid-tropics (rainforests); the arid-tropics (deserts and dry areas); or monsoon zones (those areas that have well defined wet/dry seasons and experience monsoons). Such labeling is very useful when discussing agriculture, because what works in one area of the world will normally work in a similar area somewhere else, even if that area is on the opposite side of the globe.
A staple food, sometimes simply referred to as a staple, is a food that is eaten routinely and in such quantities that it constitutes a dominant portion of a standard diet in a given population, supplying a large fraction of the needs for energy-rich materials and generally a significant proportion of the intake of other nutrients as well. Most people live on a diet based on just a small number of staples.
Staple foods vary from place to place, but typically they are inexpensive or readily available foods that supply one or more of the three organic macronutrients needed for survival and health: carbohydrates, proteins, and fats. Typical examples of staples include tuber- or root-crops, chicken, grains, legumes, and other seeds. The staple food of a specific society may be eaten as often as every day, or every meal. Early agricultural civilizations valued the foods that they established as staples because, in addition to providing necessary nutrition, they generally are suitable for storage over long periods of time without decay. Such storable foods are the only possible staples during seasons of shortage, such as dry seasons or cold-temperate winters, against which times harvests have been stored; during seasons of plenty wider choices of foods may be available.
Plant anatomy or phytotomy is the general term for the study of the internal structure of plants. While originally it included plant morphology, which is the description of the physical form and external structure of plants, since the mid-20th century the investigations of plant anatomy are considered a separate, distinct field, and plant anatomy refers to just the internal plant structures. Plant anatomy is now frequently investigated at the cellular level, and often involves the sectioning of tissues and microscopy.
Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Closely related fields include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (biochemistry of plants), cell biology, genetics, biophysics and molecular biology.
Fundamental processes such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed germination, dormancy and stomata function and transpiration, both parts of plant water relations, are studied by plant physiologists.
Hospitality is the relationship between the guest and the host, or the act or practice of being hospitable. This includes the reception and entertainment of guests, visitors, or strangers.
Science of drugs including their origin, composition, pharmacokinetics,
pharmacodynamics, therapeutic use, and toxicology.
Pharmacology (from Greek φάρμακον, pharmakon, "poison" in classic Greek; "drug" in modern Greek; and -λογία, -logia "study of", "knowledge of") is the branch of medicine and biology concerned with the study of drug action, where a drug can be broadly defined as any man-made, natural, or endogenous (within the body) molecule which exerts a biochemical and/or physiological effect on the cell, tissue, organ, or organism. More specifically, it is the study of the interactions that occur between a living organism and chemicals that affect normal or abnormal biochemical function. If substances have medicinal properties, they are considered pharmaceuticals.