Which of the following is NOT required for natural selection to occur?

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

which is an effect of short-term environmental changes? a) adaptation b) speciation c) extinction d) death (5 points)

Explain the difference between mutations in sex cell and those in somatic cells