The letter was pure puffery, probably written by some clerk in North Korea's agitprop bureau, but Trump loved it. This was the beginning of the Trump-Kim bromance.

Similarities include minimal division of the paracristid and cristid obliqua, paucity of enamel crenulations on the lophid faces and, to a lesser degree, anterior turn of the lophid ends

Free chlorine is mostly used at a low concentration (0.2–0.5 mg L -1 ) as a secondary disinfectant for the maintenance of water quality in distribution systems [3 ,9 ] or at higher concentrations as an installation disinfection treatment called hyperchlorination.

X-rays are light with a wavelength between 0.1 and 10 nm.