Vision (Definition) Vision is a feature of a person's brain that allows him to see. He must have normal eyes, optic nerves (that stretch from the eyes to the back of his brain), and visual cortex (the vision center in the brain), in order to see properly. An ophthalmologist is a doctor specializing in vision. ...Read more.
The halogens or halogen elements (/ËhÃ¦lÉdÊÉn, ËheÉª-, -loÊ-, -ËdÊÉn/) are a group in the periodic table consisting of five chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). The artificially created element 117 (ununseptium) may also be a halogen.
Volatile organic compounds are chemicals used to manufacture and maintain building materials, interior furnishing, cleaning products and personal care products. Volatile means that these chemicals evaporate or can easily get into the air at room temperature. Organic means these chemicals are carbon based. The term chemical emissions refers to VOCs as they evaporate into the air from products.