The answer is Catecholamine. It is any of a class of aromatic amines that includes a number of neurotransmitters such as epinephrine and dopamine. The adrenergic receptors are a class of G protein-coupled receptors that are targets of the catecholamines, especially norepinephrine (noradrenaline) and epinephrine (adrenaline). These three - catecholamine, peptide hormones and eicosanoids acts as extracellular membrane receptors which means that these receptors are embedded in the membranes of cells. They act in cell signaling by receiving (binding to) extracellular molecules.
Explanation:
Proteins and nucleic acids play important biological functions : they catalyze and regulate reactions, transport substrates, code and transcribe genetic information. It is widely appreciated that water molecules play an invaluable role in governing the structure, stability, dynamic, and function of these biomolecules
Water, without any doubt, must be considered an integral part of biological macromolecules. The living world should be thought of as an equal partnership between proteins, nucleic acids and water
The answer is A because cells take in glucose and oxygen and make energy, with the waste products of CO2 and H2O
