Define extinction. Explain how the fossil record can give evidence of a major mass extinction event. What evidence is there that a major mass extinction has occurred?

Will give brainliest asaapppppppppppp plz im in a major hurry to finish which of these pairs of objects exerts the greatest gravitational force on each other? object 1 and object 3 object 4 and object 3 object 1 and object 4 object 4 and object 2