germ layer: (embryology) any of the 3 layers of cells differentiated in embryos following gastrulation
tissue: part of an organism consisting of an aggregate of cells having a similar structure and function
potassium chloride: salt of potassium (KCl) (trade names K-Dur 20, Kaochlor and K-lor and Klorvess and K-lyte); taken in tablet form to treat potassium deficiency