Please help out with the question 1-3 all of them.

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

Solutions to environmental problems in europe must

Aplant may open end close its stomata to prevent excess water loss and maintain