T-lymphocytes are created in the bone marrow and then developed in the spleen.

adenoids.

thymus.

tonsils.

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

2. which is the last step in the scientific method?

Which of the following is an eon in the time scale? phanerozoic proterozoic archean all of the above