How does the immune system protect itself from pathogens

Asap! how does the distance between two objects affect the force of gravity? how is the moon dependent on the sun?

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

Which of the following is a common response to cell signaling?