Answer from cs61c-ba (Zhou Zhou 16250641) for Question 1
While statements can be replaced by a combination of if and goto statements.  Do while statements can also just be replaced with some repeating code within and without a loop.  They are all included because it allows for better program control, allows for easier coding by enforcing certain control pathways on the coder and the computer as well as allowing bad programming style to be avoided (in the case of the usage of if and while structures instead of goto statements)