answers:

7
error
8
unspec
A->num
num->num
box-n-ptr

1.
box-n-ptr.. tail is end of list

2.
(define (empty-queue)
  nil)

3.
(define (enqueue x q)
  (if (null? q)
      (list x)
      (cons (car q) (enqueue x (cdr q)))))
(define (enqueue x q)
  (fold-right cons (list x) q))

4.
(define (dequeue q)
  (cdr q))

5.
(define (head q)
  (car q)

6.
(map (lambda (x) (* x x)) lst)

7.
(filter (compose not even?) lst)

8.
(map (lambda (x) (list x x)) lst)

9.
(fold-right list nil (map list (filter even? lst)))

10.
(fold-right
 (lambda (x max)
  (if max
      (if (> x max)
          x
          max)
      x))
 #f
 lst)

11.
(fold-right
 (lambda (x last)
  (if last
      last
      x))
 #f
 lst)