The correct answer is protein.
Proteins are macromolecules composed of amino acids with the wide range of structures. Protein functions are diverse:
• structural proteins-maintaining the cell shape, (for example, proteins are structural elements in connective tissues like cartilage and bone in vertebrates),
• Enzymes - catalyze the biochemical reactions in cells-.
• Monitors- changing their activity in response to metabolic signals
• Part of the extracellular matrix or involved in intercellular communication…