Pulmonary arterial hypertension is a rare but severe disease with an estimated five-year survival rate of only 57% after diagnosis, according to the Registry to Evaluate Early And Long-term PAH disease management (REVEAL), which registers data from patients in the United States.
Concentration of elements in the ocean relative to the total concentration in the bulk silicate Earth (BSE). Of all the elements, only Cl and Br have a significant fraction in the ocean (see inset), indicating the extreme hydrophilic character for the heavier halogens.
Chlorine has been around and used by man in various forms as salt and other compounds. It is interesting that even up to the day it was isolated and discovered by Carl Wilhelm Scheele it wasn't identified as such but as another compound. It was only later in 1810 that it was acknowledged as an element and made part of the periodic table.