The correct answer is: D. all of the above
A macromolecule is a large molecule present in the cell, composed of a huge number of monomer units with the various functions. There are four main groups: proteins (monomers are amino acids), nucleic acids (monomers are nucleotids) , lipids (monomers are free fatty acids) and carbohydrates (monomers are simple sugars such as glucose).
Some of their functions:
• Provide structure on the cellular levels-lipids (phospholipids) are the main components of the cell membrane;
• store genetic material-nucleic acid (DNA, RNA) are the carriers of genetic information
• store energy-starch is energy source in plants;
• enzymes -proteins often are with the functionin metabolism
• etc.