Health

Health is the level of functional and metabolic effectiveness of an organism at both the micro and macro level. In the medical field, health is commonly defined as an organism's skill to efficiently respond to challenges and effectively restore and maintain a state of balance, known as homeostasis.

Another widely established definition of health is that of the World Health Organization which states that health is a state of complete physical, mental and social well-being and not merely the nonattendance of disease or infirmity .In more recent years, this statement has been customized to include the ability to lead a socially and economically productive life. The definition is not without criticism, as some argue that health cannot be defined as a state at all, but must be seen as a process of incessant adjustment to the changing demands of living and of the changing meaning we give to life.

Color

Color is the visual perceptual possessions corresponding in humans to the categories called red, yellow, white, etc. Color derives from spectrum of light distribution of light energy versus wavelength interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical condition of color are also associated with objects, materials, light sources, etc., based on their physical properties such as light absorption, reflection, or emission spectra.

Typically, only features of the composition of light that are visible by humans wavelength spectrum from 400 nm to 700 nm, roughly are included, thereby objectively relating the psychological phenomenon of color to its physical specification. Because perception of color stems from the varying sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantify by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully clarify the psychophysical perception of color appearance.

The science of color is sometimes called chromatics. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic emission in the visible range that is, what we commonly refer to simply as light.

Elephant

The elephants are a family of pachyderm, and the only remaining family in the order Proboscidea in the class Mammalia. Elephantidae has three living species: the African Bush Elephant, the African Forest Elephant , and the Asian Elephant .Other species have become extinct since the last ice age, which ended about 10,000 years ago, the Mammoth being the most famous of these.
Elephants are mammals, and the largest land animals alive today. The elephant's gestation period is 22 months, the longest of any land animal. At birth it is common for an elephant calf to weigh 120 kg . An elephant may live as long as 70 years, sometimes longer. The largest elephant ever recorded was shot in Angola in 1956. It was male and weighed about 12,000 kg ,with a shoulder height of 4.2m , a meter taller than the average male African elephant. The smallest elephants, about the size of a calf or a large pig, were a prehistoric variant that lived on the island of Crete until 5000 BC, possibly 3000 BC.
Elephants are symbols of wisdom in Asian cultures, and are famed for their exceptional memory and high intelligence, rivalled only by cetaceans and hominids.
Elephants are increasingly threatened by human intrusion. Between 1970 and 1989, the African elephant population plunged from 1.3 million to about 600,000 in 1989; the current population is estimated to be between 400,000 and 660,000. The elephant is now a protected species worldwide, with restrictions in place on capture, domestic use, and trade in products such as ivory. Elephants generally have no natural predators, although a pride of 32 specialized lions in Savuti, Chobe National Park, prey on elephants at night