The clusters of pancreatic cells secreting hormones are called

What is an animal that lives by preying on other animals

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

How does secondary succession differ from primary succession?