What happens when we lack our essential macromolecules ?

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!

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

Eutrophication caused by human nutrient pollution.