: A tree in which the degree of each node is either O or 2 a. b. c. d. e. Proper binary tree. Complete binary tree. Binary search tree. Strictly binary tree. None of the above. 18. One difference between a queue and a stack is: a. b. c. d. e. Queues require linked lists, but stacks do not. Stacks require linked lists, but queues do not. Stacks use two ends of the structure, queues use only one. Queues use two ends of the structure; stacks use only one. None of the above