One gene controls the synthesis of one

A gene is the set of specific nucleotide sequences, which is present on a chromosome at certain specific places. A gene is responsible for the determination of the traits of any individual. A gene helps in the expression of these traits by the formation of the polypeptides. A gene controls the synthesis of these polypeptides, which then expresses the concerned traits.

Hence, the answer is 'polypeptides'.

not the best question format lol but what i think might as scale color is controlled by a single gene with two alleles, the green allele and the yellow allele. when moths that are homozygous for green scales are mated with moths that are homozygous for yellow scales, 100% of the offspring have green scales.