The basic principle to know is that defined terms can be clearly described, whereas undefined terms are not because of its sheer simplicity. Sometimes, undefined terms are just entities that describe themselves only by using their terms. Some examples would be, 'point' and 'line'. Thus, the answers would be
Undefined terms can be used to define other mathematical concepts.
Defined terms have a clear meaning for all aspects of the concept.
Defined and undefined terms can be represented by drawings and diagrams.
