Answer:
3 . Monomers
Explanation:
monomer is the term for a singular string
<span>The research shows that the relationship between estrogen and verbal tasks is negative while it is positively correlated with spatial tasks. This correlation shows that, like in other animal studies, there could be some sort of organizing of the brain that goes on related to the level of sex hormones in the body.</span>
The primary structure of a protein always refers to the seqeunce of the amino acids inteh polypeptide chain - so the answer is the first one the polypeptide backbone (2 on the diagram).
Its like character trats like..eye color