What defines a heterozygous genotype?

A heterozygous genotype is characterized by having two different alleles for a particular gene, which often includes one dominant allele and one recessive allele. This distinct combination allows for the expression of the dominant trait while the recessive trait remains unexpressed in the phenotype under typical conditions. For example, in a plant where tall (T) is dominant over short (t), a plant with a genotype of Tt would be considered heterozygous because it consists of one allele for tallness and one for shortness. This genetic diversity plays a crucial role in the biological diversity of populations, as it can influence traits and adaptability.

The other options incorrectly describe the nature of a heterozygous genotype. Having two copies of the same trait refers to a homozygous condition, while options indicating only recessive or only dominant traits reflect purely homozygous scenarios as well, which do not encompass the definition of heterozygosity.