Answer:
The correct answer will be-alleles
Step-by-step explanation:
The instructions of the cell are decoded in a molecule called DNA nucleic acid which provides the code for every metabolic function of the cell.
The part of the DNA which codes for a specific trait is known as the gene which is present in various forms called alleles. These alleles are present on a specific location on DNA called locus.
The alleles express a trait only when the two alleles for the same trait on each chromosome complement each other after fertilization. Therefore, the allele is the correct answer.