Genetic material exchange in meiosis division by process calld?

The hematodinium parasite becomes less of a problem for the blue crab when the crab is very young. fishing is thriving in the region. the crab moves to less salty water. a significant percentage of the population is impacted.

Which is a function performed by stem cells in the skin a. replacing lost skin cells b. making cells for the intestines c. growing new organs d. differentiating into brain cells plz apex

Why has two different alleles for the same trait?