Suppose your entire herd of cows is polled, what genotype(s) can your bulls have to guarantee that you never have a calf with horns? Is this possible? Hereford cattle can be naturally “polled,” which means they do not have horns. This trait is dominant (P) over cattle with horns (p).

Once an egg cell is fertilized by sperm, the cell then, as the embryo develops, it receives nourishment and eliminates wastes by transferring substances from its blood to its mother's blood. a. becomes a fetus immediately and exits the womb b. begins to divide and implants itself in the wall of the uterus c. remains in the uterus without dividing for several months d. travels back to the ovaries until the fetus is developed