What parts of nebulas contain the most matter?

Researchers want to use edna to look for an invasive species in the water which of the steps would be likely do last

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

All organisms contribute some water to the water cycle by conducting