The specific molecular changes that occur when a drug binds to a particular target site or receptor are referred to as

Drug action.

Explanation:

Drug action can be defined, in short, as the action of the drug on the body. The effects of almost all drugs are a consequence of their interaction with macrocellular components of the body. These interactions modify the function of the relevant component and thereby initiate the biochemical and physiological changes that characterize the response or reaction to the drug. Receptors are cellular structures that have a specific purpose and that are activated in their action by different substances.

b.

hoped i

explanation:

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.