which option shows all allele combinations that can be used to represent a purebred animal
TT or tt
TT or Tt
tt
Tt
TT or tt is the correct option that shows all allele combinations that can be used to represent a purebred animal.
The correct option that shows all allele combinations that can be used to represent a purebred animal is "TT or tt."
The option that shows all allele combinations that can be used to represent a purebred animal is "TT or tt".
In order to understand why this option represents a purebred animal, let's first define what purebred means. A purebred animal refers to an animal that has a homozygous genotype for a particular trait. Homozygous means that both alleles for the trait are the same.
The letters T and t represent different alleles of a gene, with T being the dominant allele and t being the recessive allele. Therefore, an animal that is purebred (homozygous) for the dominant trait would have two copies of the dominant allele, which is represented as "TT". An animal that is purebred (homozygous) for the recessive trait would have two copies of the recessive allele, which is represented as "tt".
The option "TT or tt" includes both homozygous genotypes for the dominant and recessive traits, therefore representing a purebred animal. The other options, "TT or Tt" and "Tt", include heterozygous genotypes (one dominant allele and one recessive allele), which do not represent a purebred animal.