A plant with round seeds is crossed with another plant with round seeds. Round are dominant over oval seeds. When two heterozygous round-seeded plants are crossed, what is expected of their offspring, assuming random chromosome segregation?
Because the plants are heterozygous their alleles will be Ss (for example) Therefore if you crossed them over your possible outcome would be SS, Ss, Ss, and ss. Because the round seeds are dominant (shown as the capital S) this means that if the S is shown then the plant will have ROUND seeds. Therefore in this situation 3/4 of all the offspring would have round seeds.