There are two ____ and one __ in a tuning fork.

There are two prongs and one stem in a tuning fork.

A tuning fork is an acoustic resonator that has two prongs made of an elastic metal bar in the shape of a U and a stem. When struck on a surface or with an object it starts vibrating, it reverberates at a precise fixed pitch and emits a clean musical tone once the high overtones have faded. The length and mass of the two prongs determine the pitch that a specific tuning fork produces. To give the tuning fork a balanced motion, two prongs are offered.