Mark four points $A, B, C$ and $D$ in your notebook such that no three of them are collinear. Draw all the lines which join them in pairs as shown in figure.

Name the lines which are concurrent at $A$.

A page of a book is a physical example of a _____.

An inkpot has both              surfaces.

Two lines in a plane are either                or are                 .

Point has a size because we can see it as a thick dot on paper.