All weather activity occurs in which layer of the atmosphere?

Ineed some everybody. the production of cells during mitosis into specialized function is called: recombination or differentiation

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

Hemoglobin is a proton that carries oxygen around the body what is hemoglobin made from