A. always parallel
B. always at 90°
C. inclined at any angle 0
D. none of the above
Correct Answer: always at 90° ✔
Last Updated: December 15, 2018
A. always parallel
B. always at 90°
C. inclined at any angle 0
D. none of the above
Correct Answer: always at 90° ✔
Last Updated: December 15, 2018