Question

planes q and r are parallel planes. plane q contains line a. plane r contains line b. if a third plane could be drawn which contains both lines a and b, then lines a and b must be parallel. lines a and b cannot be parallel. lines a and b must be skew. lines a and b must be perpendicular.

Explanation:

Step1: Recall plane - line relationship

If two lines lie in the same plane and two planes are parallel, and a third - plane contains both lines, the lines must be parallel. Skew lines do not lie in the same plane. If two lines are perpendicular or non - parallel, they cannot be contained in a single plane when the original two planes are parallel.

Answer:

lines a and b must be parallel.