How many chromatids are in each replicated chromosome

Which of the following are energy solutions that release pollution into the air>

Which of these is the most likely consequence of falling petroleum price

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