Final answer:
The bass guitar plays the lead roles between vocal phrases in the song 'Drive My Car' by the Beatles, acting as a counterpoint to the vocals and giving the song its signature sound.
Step-by-step explanation:
The instrument that fills the role of a lead guitar between vocal phrases on the Beatles' song 'Drive My Car' is the bass guitar. The bass guitar plays a distinctive, melodic riff that stands out during the instrumental breaks, complementing the song's rhythm and acting as a counterpoint to the vocals. This role is usually reserved for the electric guitar, but in this case, the bass steps up to give the song its signature sound.
For a music theory class, you would learn about categorizing instruments based on how they produce sound, such as wind instruments, woodwind instruments, brass instruments, stringed instruments, and percussion instruments. Given this classification, a guitar would be classified as a stringed instrument.