Large teeth is a dominant trait in piranhas. Which of the following shows the correct probability of offspring traits if a heterozygous male and female were to
mate?

You didn't include the following

however 2 heterozygotes

build a punnett square which is a just a box with the alleles contributing from each parent one on the top and one on the side

       A      a

A    AA     Aa

a      Aa   aa

That is what would happen so 25% chance of AA and 25% of aa and 50% chance of a heterozygote

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".