;;   Question 1

(define-struct node (ssn name left right))

(define (contains-bt soc tree)
  (cond [(boolean? tree) false]
        [(= soc (node-ssn)) true]
        [else (or (contains-bt soc (node-left))
                  (contains-bt soc (node-right)))]))

[(= soc (node-ssn)) true] 

node-ssn: this selector expects 1 argument, here it is provided 0 arguments