Help!! Punnet squares

The Punnett square is a square diagram that is used to predict the genotypes of a particular cross or breeding experiment. It is named after Reginald C. Punnett, who devised the approach. The diagram is used by biologists to determine the probability of an offspring having a particular genotype

Explanation:

genotype

the answer would be a cause a dominant allele means they have the dominant trait

further Explanation: so a punnet square take two parents and crosses them to calculate the chance you will get a certain phenotype by drawing a square and splitting it in to four quarter you take the dads two genotypes and put them on the top of the square and you put the moms on the side now that you have the parents genotypes labeled you cross them the letters are there alleles so if you have a upper case allele then it is dominant meaning the offspring get the dominant trait (phenotype) now if you have two lower case letters then the offspring get the non-dominant trait (phenotype) so Bb is gets a dominant trait  BB is a dominant trait but bb is a non dominant trait the way you cross them is say you have BBxbb here's what the chart will look like

     B    B

b   Bb  Bb

b   Bb  Bb

i hoped this helped if it di please give me brainlest

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?