Absolute refractory period -
the period immediately following the firing of a nerve fiber when it cannot be stimulated no matter how great a stimulus is administered
Are you looking for an explanation or the equation?
Answer:
the answer would be D
Explanation:
it says that mono is caused by a virus that is transferred through direct contact, so it can be classified as an infectious disease. This would prevent A, B, and C from being adequet answers, because those all support reasons for mono to be a noninfectious disease.
The chemical originally contained in aerosol propellants that is thought to have contributed to the depletion of the ozone layer is the chlorofluorocarbons or the CFCs. These are nonflammable and nontoxic substances that has carbon, chlorine and fluorine in their structure. These substances are used as propellants, solvents and as refrigerants. However, it was found from researches that these substances would contribute to the depletion of the ozone layer in the atmosphere which is why under the Montreal Protocol, the use of these are banned and other alternatives are being used now in replace with the CFC. One alternative used is the <span>hydrofluorocarbons.</span>
