Which of the following must occur before mitosis can begin. Help

The spermists believed that: the male made the only hereditary contribution to the offspring the male and female traits were blended in the offspring the female made the only hereditary contribution to the offspring the male and the female made equal contributions to the next generation

Why has two different alleles for the same trait?

Fill in the blank with the best word to complete the sentence. white blood cells protect against and aid in blood clotting when injuries are sustained.