The cell membrane

is not a true organelle
contains and protects the cell
is made of a double layer of phospholipids
contains proteins that allow materials to pass through

protein makes up the building blocks of organs, muscles, skin, hormones and pretty much everything that matters in your body.

some choices are:

peanut butter

seeds

eggs

yogurt

meats

fish

so pretty much meat, dairy, nuts, and grains.

answer( increase) their individual contractile activity;