Which organelle forms the surface of a cell separating its content from the outside world?

cell membrane forms the surface of a cell to protect it from the outside world.

Cell membrane is the organelle forms the surface of a cell separating its content from the outside world.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

idk what the options are but

these is a strong electrostatic attraction between the ions hence a lot of energy is needed to overcome this attraction

this is why the boiling points are so high