What purpose of transportation? Where does it happen the cell

Explanation: How do things move across a cell membrane?

Summary. Controlling the movement of things in and out of the cell is an important role of the plasma membrane. ... Osmosis is the diffusion of water molecules across a membrane. Water moves in or out of a cell by osmosis until its concentration is the same on both sides of the plasma membrane.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

answer; i believe the correct answer is (a)0