Think of melody as the "tune" of a song, and rhythm as the "heartbeat". Just as a heartbeat provides the underlying structure for a person's life, rhythm provides the foundation for music. And just as a tune without a heartbeat would be lifeless, a melody without rhythm would be disjointed and chaotic.
In summary, melody and rhythm are like two sides of the same coin, and neither can exist without the other. They are essential components of music, and their interplay creates the rich and dynamic experience that we enjoy when listening to music.