Question

Which of the following is heterozygous?
A. TTRR
B. ttrr
C. TT
D. Tt

Answer 1

Heterozygous means that you have inherited various versions of a gene from each parent. A heterozygous genotype differs from a homozygous genotype, which means that an individual receives identical copies of a gene from both parents. A heterozygous genotype differs from a homozygous genotype, which means that an individual receives identical copies of a gene from both parents.

Complete answer:
The two alleles interact in a heterozygous genotype. This decides how their characteristics are manifested. Heterozygous means you acquired different versions of the same gene from each of your biological parents. Now, when we say distinct forms, we're referring to different parts of the gene with different sequences.
This encounter is usually based on dominance. The allele that is expressed more strongly is referred to as "dominant," and the other is referred to as "recessive." This recessive allele is disguised by the dominant one, depending on how the dominant and recessive genes interact.
Heterozygous refers to when there are two different alleles, whereas homozygous refers to when there are two similar alleles. The remaining individuals are homozygous.

Hence option D. is the correct answer.

Note:
The pairing of heterozygous alleles can occasionally translate into a higher chance of specific ailments such as birth abnormalities or genetic disorders, in addition to an individual's physical traits.A heterozygote advantage occurs when the heterozygous genotype outperforms either the homozygous dominant or homozygous recessive genotype in terms of relative fitness. Overdominance is a unique case of heterozygote advantage attributable to a single locus.