What is an enzyme? what does it do?

Which of the following examples can cause gene flow between populations? a.an increase in predators to a population of zebra b.a volcanic eruption that kills half of a population of mice c.bird droppings that contain seeds from a different location d.a person that sprays a toxin on a group of mosquitoes

What noticeable trend from this graph might be used to make a conclusion?

What do we call the process when two dominant alleles are expressed and do not blend? a.incomplete dominance b.codominance c.multiple alleles