Meningitis is a disease caused by the inflammation of the protective membranes covering the brain and the spinal cord. While most people with meningitis recover, it can cause serious complications, such as brain damage, hearing loss or learning disabilities. A vaccination is the most effective way to protect yourself against certain types of meningitis.
Primary & Secondary pollutant. Definition: A primary pollutant is an air pollutant emitted directly from a source. A secondary pollutant is not directly emitted as such, but forms when other pollutants (primary pollutants) react in the atmosphere.
Black established this was a form of air, but that it was different from 'common elastic air'. He reasoned that this air must have been 'fixed' within the magnesium compound, so called it 'fixed air'. He noted that fixed air: 1  Was heavier than common air. 2  Could extinguish a flame. 3  Would suffocate an animal.