OVERBURDEN   :   

The rock and dirt that overlie a mineral deposit and that must be removed before the mineral deposit can be extracted by surface mining.

OVOID   :   

Shaped like an egg.

OVULATION   :   

The process of menstruation cycle in females, in which the the mature ovarian follicle ruptures to discharge an ovum or egg to participate in reproduction is known as Ovulation.

OXIDATION   :   

Chemical reactions involving different types of chemical conversions such as (1) loss of electrons by a chemical, (2) combination of oxygen and another chemical, (3) removal of hydrogen atoms from organic compounds during biological metabolism, (4) burning of some material, (5) biological metabolism that results in the decomposition of organic material, (6) metabolic conversions in toxic materials in biological organism, (7) stabilization of organic pollutants during wastewater treatment, (8) conversion of plant matter to compost, (9) decomposition of pollutants or toxins that contaminate the environment.

OXIDIZE   :   

To combine with oxygen.

OXYGEN   :   

A colorless, odorless, tasteless gas that is the most plentiful element in the Earth's crust. It was discovered in 1772 by Swidish chemist Carl Wilhelm Scheele.

OXYGENATED BLOOD   :   

Blood that supplies oxygen bound to hemoglobin that is carried in red cells to the various tissues, and cells of the body is known as oxygenated blood. The heart pumps out the oxygenated blood through the important artery known as coronery artery.

OZONE   :   

A triatomic molecule consisting of three oxygen atoms. Ground-level ozone is an air pollutant with harmful effects on the respiratory systems of animals. On the other hand, ozone in the upper atmosphere protects living organisms by preventing damaging ultraviolet light from reaching the Earth's surface.