Which of the following activities can be directly linked to desertification? (1 point)
I. irrigation of cropland
II. harvest of biomass for energy
III. building of housing developments

II only
III only
I and II
I and III
II and III

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