The cell membrane serves many functions. One of the cell membranes functions is to help the cell maintain homeostasis. How does the cell membrane do that ?

The cell membrane help to maintaining homeostasis by regulating the flow of substances through it and by recognizing potentially harmful agents to the cell.

Explanation:

Cellular membrane is constituted by a lipidic bilayer, whose characteristics allow it to behave as a semi-permeable membrane to the passage of substances.

The selective permeability of the membrane makes it possible to regulate the passage of water, molecules and ions through it into the cell and from there into the extracellular space, a characteristic that allows the maintenance of homeostasis.

Additionally, the cell surface can identify foreign and potentially harmful agents, which can affect the internal balance, preventing in most cases their passage into the cell.  

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.

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