Answer from cs61c-ew (Joo-Rak Son 16103505) for Question 2
The benefits of having the VM system allocate pages in fixed-size chunks is that we can eliminate the need to find a contiguous block of memory to allocate to a program. Instead, the operating system can only find sufficient number of usable pages here and there.
Bigger chunks may be desireable because the page fault in virtual memory takes too many cycles. If our blocks are bigger, then the miss rate may decrease.
Smaller chunks may be desireable because it's easier to implement and we'll be allowed to have more pages in the virtual memory.