(define (filter-lst fn lst) 'YOUR-CODE-HERE)

; ;; Tests
(define (even? x) (= (modulo x 2) 0))

(filter-lst even? '(0 1 1 2 3 5 8))

; expect (0 2 8)
(define (interleave first second) 'YOUR-CODE-HERE)

(interleave (list 1 5 3) (list 2 4 6))

; expect (1 2 5 4 3 6)
(interleave (list 1 3 5) nil)

; expect (1 3 5)
(interleave (list 1 3 5) (list 2 4))

; expect (1 2 3 4 5)
(define (accumulate combiner start n term)
  'YOUR-CODE-HERE)

(define (without-duplicates lst) 'YOUR-CODE-HERE)