Https://www.education.com/reference/article/basis-high-scope-curriculum/ Click the link and it will tell you the basis. I would have just told you, but I don't understand it.
GOUACHE is watercolor that has been made opaque by adding inert white pigment to it.
Further expounding this, it is commonly diluted with water before being applied to paper. However, Gouache is opaque in its natural state. It becomes translucent when a larger amount of water is used to dilute the paint.
Body colour is the use of opaque colours for highlights or dense flat areas and is a technique which has been used in water colour for centuries.
