Answer from cs61c-cf (Aspandiar Dahmubed 16812056) for Question 2
Having read ahead, I know of the addi instruction that can be used to add a integer to a variable (in this case 1)
addi k, k, 1

but a long, unnecessary convoluted way could be done using (assuming here that k > 0)
slt $t0, $zero, k ($t0 == 1 if k > 0)
add k, k, $t0 (k = k + 1)