Answer from cs61c-ea (Jeff Decker 16217761) for Question 2
A programming language that does not use recursion would not need to allocate frames on the stack. Hence, all the steps having to do with the frame could be elimninated and each procedures frame would be statically allocated at compilation/linking time.

Hmm, I took cs61a about 2 years ago so I don't remember the problem with scheme, but I can say that recursion is a tough concept for most programmers (new and experienced) so there can be a lot of hard to find bugs created with it.