The worm and worm wheel both are threaded screw.
(a) True
(b) Worm wheel is a toothed gear
(c) Worm is a toothed gear
(d) None of the listed
Someone asked me this question by my college professor while I was bunking the class.
Question is from the Worm Gears section in part Bevel Gears, Worm Gears and FlyWheel of Machine Design