Alto Line: The alto line is the second-highest melodic line, usually sung by female voices. It harmonizes with and supports the soprano line.
Tenor Line: The tenor line is typically sung by male voices and falls between the alto and bass lines. It adds depth and richness to the overall harmony.
Bass Line: The bass line is the lowest melodic line, often sung by male voices. It provides a solid foundation for all other voices and helps create harmonic stability.