What type of loop checks a Boolean expression at the "top" of the loop before the body has a chance to execute?

To access parts of the screen that are otherwise hidden from view, use the ________

A) scroll bar B) mouse C) start button D) insert key

A binary tree:

a. Has a root node. b. Each node has no more than two branches. c. Uses stacks to process the nodes. d. Uses two extra fields for the pointers to the branches. e. All of the above.