Microorganisms developed from more complex organisms?

Oxygen played a key role in the evolution of complex organisms, according to new research published in BMC Evolutionary Biology. The study shows that organisms containing more varied cell types evolved following increases in atmospheric oxygen.

Hope it helps uh.

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c

i believe it is c: genes for body color and wing size are inherited separately from each parent.