Cyclic adenosine monophosphate is a substance that performs which of the following?

Cyclic adenosine monophosphate (cAMP) acts as a secondary messenger that remains at the cell surface. (It is made by adenylate cyclase).
cAMP is a small molecule that is produced inside cells in response to signals from hormones and other molecules. It acts as a messenger molecule, carrying signals from the cell surface to the inside of the cell.
cAMP can bind to a variety of proteins inside the cell, which can then trigger a variety of cellular responses, such as gene expression, enzyme activation, and cell division.