Each trait of a plant is determined by

The correct answer will be-alleles

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.