Final answer:
The Beach Boys' first number-one hit on the Billboard Hot 100 chart was "I Get Around," which was achieved in 1964 and is known for its notable harmonies and catchy melody.
Step-by-step explanation:
The Beach Boys were a seminal American rock group known for their close vocal harmonies and lyrics reflecting a Southern California youth culture of surfing, cars, and romance.
Their first number-one hit on the Billboard Hot 100 chart was "I Get Around." This milestone occurred in 1964 and marked a significant moment in the band's career, cementing their status as one of the leading acts of the 1960s.
I Get Around features the band's signature sound with catchy hooks and intricate harmonies, making it an enduring classic in popular music history.