Science

Preservative Definition Preservative is a substance added to food products or to organic solutions to prevent decomposition due to chemical change or bacterial action. In…

Fibroblast Definition Fibroblast is a cell that manufactures and maintains connective tissue, the structural framework that supports the organs of all animals. It is responsible…

Penicillium Definition Penicillium is any of various bluish-green fungi of the genus Penicillium, that grow as molds on decaying fruits, ripening cheeses, and bread, and…

Atomic Clock Definition Atomic clock is an extremely precise clock whose rate is controlled by a periodic process, such as vibration, or the absorption or…

About Common Cold Definition Common cold is a respiratory infection caused by any of several viruses, such as adenovirus or rhinovirus, in which the mucous…

Vitamin C Definition Vitamin C is a water-soluble vitamin important for healthy skin, teeth, bones, and blood vessels. It is found especially in citrus fruits,…

Complementary Angles Two angles are complementary if the sum of their angles equals 900. A common case is when they form a right angle. If…

Gland Definition Gland is an organ or group of specialized cells in the body that produces and secretes a specific substance, such as a hormone.…

Sodium Nitrite Definition Sodium nitrite is a white crystalline compound used to lower systemic blood pressure, to relieve local vasomotor spasms, to relax bronchial and…

Caesium Definition Caesium is a soft, ductile, silvery-white element of the alkali group. It is liquid at room temperature and is the most reactive of…

Nitrous Oxide Definition Nitrous oxide is a colorless, sweet-smelling gas. It is used as a mild anesthetic, often called laughing gas. Nitrous oxide occurs naturally…

Epithelium Definition Epithelium is the thin, membranous tissue that lines most of the internal and external surfaces of an animal’s body. It is composed of…