Answer:
The barrier functions to regulate the chemical composition of the extracellular fluid surrounding the brain cells.
Explanation:
Blood-brain barrier
It is a very selective semipermeable membrane , hence allow some specific substance to pass via it . This barrier separates the extracellular fluid in the central nervous system and the circulating blood from the brain .
<u>The barrier is composed of the endothelial cells .</u>
Passive diffusion is shown in this system , and allows molecules like the water , glucose , amino acid to pass .
It regulates the chemical composition of the fluid of brain cell .
<span>Plants use energy from sunlight to turn water and carbon dioxide into an energy-rich sugar called glucose. </span>
It is true that cells spend most of their time dividing. In fact, they spend 78% of their "life" in interphase.