Answer from cs61c-eg (Ramanarayan Vasudevan 15938560) for Question 1
It doesn't need all of them. All that is needed is if statements and gotos. The other two can be dropped. The designers of C included all of them for greater simplicity and flexibility to the programmer. Although the programmer could survive with only those two, only having the two can lead to bugs and make programming a bit more cumbersome.