Answer from cs61c-aj (Kevin Li 15855812) for Question 1
It is the the instruction slot immediately following the branch instruction. No matter if the branch is taken or not the branch delay slot is always executed. This is because hardware is implemented so that it will not be slowed down. In case if the branch is not taken no time is wasted on a useless stall. If it is taken then the branch delay slot instruction that is executed is tossed and ignored.