“For every line x and for every point o not lying on x, there exists a unique line y passing through o and parallel to x.” This statement is __________

Equivalent Versions of Fifth Postulate: If a straight line falling on two straight lines makes the interior angles on the same side of it taken together less than two right angles, then the two straight lines, if produced indefinitely, meet on that side on which the sum of angles is less than two right angles.