> (+ 1 2 3 4)
10

> (+ (list 1 2 3 4))
+: expects argument of type <number>; given (1 2 3 4)

> (apply + (list 1 2 3 4))
10

> (reverse (list 1 2 3 4))
(4 3 2 1)

> (reverse 1 2 3 4)
reverse: expects 1 argument, given 4: 1 2 3 4

> (apply reverse (list 1 2 3 4))
reverse: expects 1 argument, given 4: 1 2 3 4

> (define (reverse-1 . x) (reverse x))

> (reverse-1 1 2 3 4)
(4 3 2 1)

> (apply reverse-1 (list 1 2 3 4))
(4 3 2 1)