arsenic
Nitrogen group element, any of the chemical elements that constitute Group 15 (Va) of the periodic table. The group consists of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi), and moscovium (Mc).
<span>There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart</span>
By the ligand receptors on the surface of the cell membrane. How do transport proteins make it easier for certain molecules to diffuse across a membrane.
the binding of a signaling molecule, or ligand, to its receiving molecule, or receptor.