$A$ pyramid is a solid figure,the base of which is

The boundaries of the solid are ...........

$A$ surface is that which has $\ldots \ldots \ldots$ only.

State whether the following statement is True or False. Justify your answer.
Euclidean geometry is valid only for curved surfaces.

Read the following two statements which are taken as axioms:
$(i)$ If two lines intersect each other,then the vertically opposite angles are not equal.
$(ii)$ If a ray stands on a line,then the sum of two adjacent angles so formed is equal to $180^{\circ}$.
Is this system of axioms consistent? Justify your answer.

The side faces of a pyramid are: