Solve part a, b,c

I will give brainliest to best answer

A) the variable he changed was not heating tube q, i think
b) two constant variables were the amount of starch solution added and the time he waited
c)Nakula’s results support his conclusion because he only boiled tube p which is the tube that showed no sugar.

Answer d would be the best answer, for he wants to have part in biotechnology. an ekg technician is quite similar.