What is cell differentiation? give one example.

Describe the response the kidneys have to dehydration and excessive water intake. what happens to the concentration of urine in each case ?

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

The variation among individuals, on which natural selection acts