Which option shows all allele combinations that can be used to represent a purebred animal?
TT or Tt
tt
TT or tt
Tt
TT or tt.
The 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."
To understand why, let's first discuss what alleles are. Alleles are different forms of a gene that determine certain traits in an organism. For example, in this case, we are talking about a gene that determines the trait of "tallness" in animals.
In general, an organism inherits two alleles for each gene, one from each parent. These alleles can be either dominant or recessive. Dominant alleles are denoted by capital letters, while recessive alleles are denoted by lowercase letters.
A purebred animal is one that has two identical alleles for a particular trait. In the given options, "TT or tt" represents a purebred animal because it has two copies of the same allele, either two dominant alleles (TT) or two recessive alleles (tt), both of which would result in a purebred animal for the trait of tallness.
The other options, "Tt" and "tt," do not represent purebred animals. "Tt" represents a heterozygous individual (having two different alleles) with one dominant allele (T) and one recessive allele (t). And "tt" represents a purebred animal for the trait of shortness, as it has two recessive alleles.
Therefore, the correct option is "TT or tt" to show all allele combinations that can be used to represent a purebred animal.