Fluid does wat to each cell

The interstitial compartment (also called "tissue space") surrounds tissue cells. It is filled with interstitial fluid, including lymph. Interstitial fluid provides the immediate microenvironment that allows for movement of ions, proteins and nutrients across the cell barrier.

Explanation:

the Fluid will fills and surrounds the cells.

Part 1) the answer to the first part of this question is that sara used the most appropriate units to measure the mass of the planets.

part 2) it would take an incredible amount of time just to write out how much a single planet weighed using milligrams. miligrams are better used to measure something which requires a high amount of accuracy - we cannot accurately measure the mass of the planets to this extent.