Answer:
both parents (sperm and egg) combine chromosomes during mieosis to create two identical daughter cells with that only one of the daughters cells is fertile
so the daughter cells differ because only one is fertile
In natural selection, a species is changed due to a random mutation in offspring that means the offspring is better adapted to survival in that specific environment. As this offspring grows, it out competes it's rivals and they die off leaving it to survive and reproduce passing it's beneficial allele to its own offspring. This chain of passing on the beneficial allele continues until the majority has the beneficial allele meaning the species has evolved.
Genétic problems or diseases
