Answer:Because of where they are from.
Explanation:
Geographic, or physical, barriers result in geographic isolation
Answer: crossing over
during the process of fertilization, a sperm and egg join together to create a zygote. since a sperm had half the number of chromosomes and an egg has half the number of chromosomes, when they join together the zygote had a complete diploid set of chromosomes. the assortment of chromosomes and crossing over promotes genetic variation during the process of reproduction
Answer:
Impulsive behavior
Explanation:
They don't think before they move or do something and it is normally something that could cause harm or get into trouble.