Fermentation is a metabolic process that converts sugar to acids, gases, or alcohol. It occurs in yeast and bacteria, and also in oxygen-starved muscle cells, as in the case of lactic acid fermentation.
pupil noun [C] (EYE PART). âº the âcircular âblack âarea in the âcentre of an âeye, through which âlight âenters: Pupils âcontract in âbright âlight, and âdilate in darkness. (Definition of pupil from the Cambridge Advanced Learners Dictionary & Thesaurus Â© Cambridge University Press).
The pupils look like round, black dots in the center of the eyes, but they are actually openings that allow light to enter the eyes. The size of the opening is controlled by the iris, the colored portion of the eye surrounding the pupil. The pupils constantly change size in response to light, to the eyeâs focusing distance, and to emotions. Normally, the pupils dilate (enlarge) in darker conditions to allow more light to enter the eye. The medical term for dilated pupils is mydriasis. Medications or other drugs can also cause the pupil to dilate, either intentionally or as a side effect. For example, eye care professionals often use eye drops that dilate the pupils in order to examine structures at the back of eye, such as the retina.