Primary productivity is the rate at which _ make organic matter

Explain how fossils scientists make discoveries about the lives of organisms and about how environments have changed over time. plz hurry up it time

Advances in technology have enabled scientists and researchers to better study the evolutionary relationships between species

Ialready know the answers to these questions and they are on the attachment. but i just need to know why that answer is the correct one. plz asap! this is for a report that i need to email by 10!