The invisible barrier that hinders women and minorities from advancement up the corporate ladder
a. is the comparable worth issue.
b. is known as the glass ceiling.
c. has been ignored by congress.
d. has been reinforced by use of set-aside contracts.

A diagram is a symbolic representation of information using visualization techniques. Diagrams have been used since ancient times on walls of caves , but became more prevalent during the Enlightenment.[1] [2] Sometimes, the technique uses a three-dimensional visualization which is then projected onto a two-dimensional surface. The word graph is sometimes used as a synonym for diagram.