This means that water tends to move

Osmosis

Explanation:

I believe you are asking the concept in which water tends to move in a cell, which is called osmosis.

Cells have semipermeable membranes, which means that not all substances are able to enter or leave the cell.

Osmosis permits the movement of a solvent across this semipermeable membrane (see image below). During this process, water moves from an area of high concentration to an area of lower concentration of water.

straight or amphibians are homeothermic to thermal

that is wrong, its not thymus.