Organisms that have two identical alleles for a particular trait are said to be

Homozygous

Explanation:

The obvious traits in living organisms are usually controlled by molecular structures called GENES. A gene exists in two contrasting forms called ALLELES. Based on this, there are two different alleles for two different traits in a gene.

An organism that contains the same/identical alleles for a particular trait is said to be genotypically HOMOZYGOUS while an organism that possesses two different alleles for a particular trait is said to be HETEROZYGOUS.

For example, height trait controlled by a single gene that possesses two alleles: T for tallness and t for shortness. An organism that has two identical alleles e.g TT and tt is said to be homozygous for that trait while an organism that possesses Tt is heterozygous.

answer; i believe the correct answer is (a)0