When a transversal crosses two parallel lines, same-side interior angles are supplementary, so their measures add to $180^{\circ }$. Since angle 1 is $68^{\circ }$, angle 2 is $180^{\circ }-68^{\circ }=112^{\circ }$. Therefore, the correct answer is $112^{\circ }$.

When two lines intersect, adjacent angles form a linear pair, so their measures add to $180^{\circ }$. If one angle is $68^{\circ }$, then an adjacent angle is $180-68=112^{\circ }$. Therefore, the statement that must be true is that an adjacent angle has measure $112^{\circ }$.

Adjacent angles formed by two intersecting lines make a linear pair, so they are supplementary. That means their measures add to $180^{\circ }$. The angle adjacent to $68^{\circ }$ is $180-68=112$. Therefore, the correct answer is $112^{\circ }$.

When two lines intersect, adjacent angles form a linear pair, so their measures add to $180^{\circ }$. If one angle is $68^{\circ }$, then an adjacent angle measures $180-68=112$. Therefore, the correct answer is $112^{\circ }$.

First find the slope of line $p$ using the two points:

For a line that makes an angle $\theta$ with the positive $x$-axis, the slope is $\tan \theta$. So:

The acute angle whose tangent is 1 is $45^{\circ }$. Therefore, the correct answer is $45^{\circ }$.