A. <span>A flatworm doesn't have a coelom
Flatworms and other invertebrates belong to a specific group called </span><span>acoelomate, wherein they lack a coelom and has an internal cavity which serves as their digestive cavity.</span>
For this question I'm not too sure what you're asking because cells that transport water are basically xylem cells and these cells are hollow with nothing in them, and they transport water against gravity because of transpiration pull, capillary action and root pressure.
The cells that I know of with many mitochondria for transport would be the phloem so that the mitochondria can carry out cellular respiration to release energy for the translocation of sucrose.
There are three types of waste water
sewage: domestic sewage, industrial sewage, and storm sewage
Cell maintain homeostasis through diffusion in isotonic solution. Isotonic means that the concentrations are the same on either side of the membrane, maintaining homeostasis.
