Mosaics are __________________a.images made with glass that has been colored by metallic salts are pieced together like a collage, and are joined by leading.b.images made by arranging colored pieces on a flat surface, which are held using leading.c.artwork created by arranging cut out or torn material pasted onto a surface. Means "to glue" in French.d.images made by arranging stones or tiles that are then embedded with a filler to connect the colored pieces.