How does crossing over add to the genetic diversity of sexually reproducing organisms?

The response is the basis for vaccination. primary secondary tertiary none of the above

Why does the earth spin slowly, not faster? is it possible to prove it scientifically? can you prove it with math?

Neeed now for 1. eye color is a polygenic trait. what is the possibility of getting a green (aabb) eyed child, if parent 1 has brown eyes (aabb) parent 2 has blue eyes (aabb) 2.albinism is a recessive trait. having normal pigment is the dominant trait. what is the possibility of having an albino child if parent 1 is heterozygous normal parent 2 is heterozygous normal 3.in rabbits black fur is dominant over white fur. what is the probability of getting a rabbit with black fur if parent 1 is heterozygous black parent 2 is homozygous white