Why is deep ocean water almost completely isolated from the atmosphere?

deep water is covered with a thick layer of sea ice.

(70pts)

deep water is too dense to rise up and mix with surface water.

deep water cannot flow, so it is only influenced by the water over it.

deep water is very light and so it flows too rapidly to contact the atmosphere.

that is wrong, its not thymus.

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.