How does the human eye work ( playgarism free)

The front of the eye has an adjustable hole in it called the pupil, covered by a spherical “window” known as the cornea. Light passes through these structures to the lens, a (normally) transparent focusing device controlled by muscles and ligaments. The focused light shines through the fluid-filled interior of the eye to the retina at the back of the eye. The retina contains specialized cells(rods and cones) that react to brightness, darkness and color frequencies, sending this information through the optic nerve to the brain for visual processing...remember that never impulses control the blinking of eye not the release of hormones.

oxygen is the first element in group 16 (via) of the periodic table. the periodic table is a chart that shows how chemical elements are related to each other. the elements in group 16 are said to belong to the chalcogen family. other elements in this group include  sulfur, selenium, tellurium,  and  polonium.  the name chalcogen comes from the greek word  chalkos,  meaning "ore." the first two members of the family, oxygen and sulfur, are found in most ores.

oxygen is by far the most abundant element in the earth's crust. nearly half of all the atoms in the earth are oxygen atoms. oxygen also makes up about one-fifth of the earth's atmosphere. nearly 90 percent of the weight of the oceans is due to oxygen. in addition, oxygen is thought to be the third most abundant element in the universe and in the solar system.