Answer:
The reason for Mary's resemblance to her mother is that; one of her mother's genes was dominant, while that of her father were recessive.
Step-by-step explanation:
A gene, alleles, is a genetic code that has some individual traits that can be transferred from parents to their offspring.
Dominance shows the relationship between two different genes. Each parent donates two alleles each to their offspring. In the case of different alleles donated, one would be expressed more than others called dominant gene if the alleles are different. While the others would be recessive. Thus, the characters or traits of the dominant gene would be obvious on the offspring.
Mary's resemblance to her mother was due to her mother's gene which was dominant compared to that of her father.