Can u answer question 4 please

What did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere, b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify, d)anaerobic bacteria kept thriving with more oxygen

The picture represents a structure of the respiratory system. which is the function of this structure? to bring air into the body to exchange oxygen with carbon dioxide to carry air to the lungs to release oxygen from the body

How are fossils used to date organisms?