The main function of this macromolecule include muscle development, catalyst activity and defense against disease

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 ...