Answer from cs61c-ar (Albert Chung 15826273) for Question 2
3 of them.  beq, bne, and slt.  beq and bne check for equality: beq branches if equal and bne branches if not equal.  slt checks to see if one value is larger than the other (set on less than).  The designers of MIPS probably wanted to keep the instruction set small and simple to make the system fast, leaving the complicated part to the software.