They are used as "id" tags
To increase the Strength and Impermeability of the 'outer bi-lipid layer'. There are many other functions, as well! (Note: the inner bi-lipid layers are the endoplasmic reticulum.)
it protects the cell and if the cell didn't protect it the cell would die.
regulation of what goes into and out of the cell
its to protect the cell from damage, and keeps some substances and others out. OMG DO YOU HAVE A BIO TEST D:
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