I think for your distilled water of 1 it would look like 27.8 +/- 5 because you can go 5 above or below your average and 2 would be 27.8 +/- 10 because you can go 2 times below or above your average?
Answer:

The force that blood exerts against the wall of a vessel is called <u>blood </u><u>pressure</u><u>.</u>
Class 10 - NCERT Book - definition.

Answer:
The plasma membrane, or the cell membrane, provides protection for a cell. It also provides a fixed environment inside the cell, and that membrane has several different functions. One is to transport nutrients into the cell and also to transport toxic substances out of the cell.
Explanation:
1. The Cell Wall.
Plants have a cell wall in order to maintain rigidity and stability. Animal cells do not have a cell wall because they have a different structure, which makes them more flexible and able to move around easier.
2. Chloroplasts
Since plants cannot move, they get their energy from the sun. This energy is made inside of the chloroplasts. Animal cells don't have chloroplasts because their energy comes from other organisms.
3. Central Vacuole
The central vacuole provides structure and holds materials and wastes, and also decomposes those wastes. Animal cells don't have a central vacuole because they have lysosomes and normal vacuoles that do the same function.