It may or may not turn acidic depending on the area or time of the year it is.
<span>a. Acoelomates. Flatworm is a type of acoelomate animal; they have no body cavity or ceolom but they have </span>mesenchyme in their body cavity that surrounds the gut and organs in one solid body.
In this question in which is the major source then of free oxygen in the earth's Proterozoic atmosphere is being produce by the evaporation of the ocean water. Hope this answer would be of big help to this assignment then.
