the plasma membrane a. is rigid and impermeable b. is free of proteins c. is permeable to ions and polar molecules d. is composed mostly of cholesterol e. controls the contents of the cell

bilayer

Explanation:

The plasma membrane is SEMIpermeable, it can allow certain materials like nonpolar molecules to pass though its membrane so choice A is wrong. Choice B is also wrong because the plasma membrane is a phospholipd bilayer, meaning it has proteins. Choce C isn't correct  because cholesterol is not composing most of the membrane.

Choice E is your best answer because the most important function of the plasma membrane is to control what enters and exits the cell.

Hope this helps and makes sense to you! Good luck.

answer; (phospholipid);

hey bro i looked it up on google the structure of the eye-spot in euglena viridie, e. ehrenbergii, and phacus pyriyorme is not as franzé haa described it. the so-called “crystal body” and “lens bodies” were not found in any of the individuals of the species examined by me. as earlier observers have stated, the eye-spot consists simply of a mass of pigment granules arranged in a single layer, and probably embedded in a protoplasmic framework, but the latter could not be seen, and its presence was only inferred from the fact that the pigment granules must be held together in some way, thd the eye-spot as a whole is capable of expansion, and that the pigment granules can be separated from each other.

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