I’m sexually reproducing animals once fertilization of the egg place , the exists as a single cell until cell division begins

What is an animal that lives by preying on other animals

What is the following best defines climate?

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