Answer:
lipids
Explanation:
There are four major biological macromolecules in living systems viz: carbohydrate, proteins, lipids and nucleic acids. These macromolecules play a significant role in the optimal functioning of every living organism. Like every other polymer, these macromolecules are made up of simpler units called monomers that defines their chemical structure. In turn, the monomers consists of chains of chemical elements held together.
According to the question, Sebastian has colored balls that represents the elements contained by each of these macromolecules. The colored balls and the elements they represent are as follows: Red: hydrogen, Black: carbon, Purple: oxygen, and Green: nitrogen.
Lipids are structurally made up of fatty acids and glycerol, which are long chains of carbon and hydrogen elements with a relatively small percentage of oxygen in the structure. An example is palmitic acid, which has a structural formula: CH3(CH2)14COOH
Hence, Sebastian could make a LIPID macromolecule, which consists of long chains of red (hydrogen) and black (carbon) balls since lipids are mostly made up of carbon and hydrogen elements in their structure.
Carbohydrates are composed of more percentage of oxygen in their structure. Hence, a long chain of only red (hydrogen) and black (carbon) balls cannot make them. Proteins and nucleic acids are made up of additional nitrogen and phosphorus elements in their structure.
