I believe its B because bees spread pollen but take honey.
Answer choice A. Stasis.
Stasis is a block of little to no change in a species.
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 .
It is because of the different neurotransmitters and their receptors.
Sympathetic stimulation of arterioles in skeletal muscle is mediated by epinephrine acting on its β-adrenergic receptors.
Sympathetic stimulation of vasoconstriction occurs as a result of activation of α-1 adrenergic receptors by norepinephrine released by post-ganglionic sympathetic neurons.
