All living things are made up of four classes of biological macromolecules: carbohydrates, lipids, proteins, and nucleic acids.
Macromolecules are large molecules composed of thousands of covalently connected atoms, also called polymers. A polymer is a long molecule consisting of many similar building blocks; the small building-block molecules are called monomers.

All cells have thousands of different macromolecules, that vary among cells of an organism, vary more within a species, and vary even more between species. A huge variety of polymers can be built from a small set of monomers.

What statements are true about the biological macromolecules.

All biomolecules could be called carbon-based molecules.
The monomers of DNA are nucleotides.
Ready cellular energy comes in the form of lipids.
Carbohydrates contain nitrogen and therefore differ from the other macromolecules
Cell membranes are made, in part, from phospholipids.
The monomers of of starch are monosaccharides.