HIV is the virus that causes AIDS. In the mid-1990s, researchers discovered an enzyme in HIV called protease. Once the enzyme's structure was known, researchers began looking for drugs that would fit into the active site and block it. If this strategy for stopping HIV infections were successful, it would be an example of what phenomenon?

A. noncompetitive inhibition
B. denaturation
C. allosteric regulation
D. competitive inhibition

Explanation:

If the strategy of using a drug that binds to the active site of the enzyme and block it proves successful, then the phenomenon taking place is :

D. Competitive inhibition.

A competitive inhibitor of an enzyme is a molecule that closely resembles the substrate and binds to the active site of the enzyme and blocks its . Competitive inhibition is a reversible phenomena and it can be reversed by increasing the substrate concentration.

stratosphere: as the altitude increases, the air temperature increases. the stratosphere has a layer of ozone, called the ozone layer. this layer absorbs most of the ultraviolet radiation from sunlight. this results in the stratosphere being warmer.