On the periodic table it is the number on the bottom of the element.
<span>If you know the amount of neutrons you can add it to the number of protons to find the atomic mass NUMBER, which is a good approximate of the atomic mass. </span>
The cell membrane performs those functions. It is the outer layer of a cell and it creates a barrier, regulates material entry and exit, uses chemical signals, and creates structure.
Answer:
Because scientists call vaccines reagents.
