If drug a has an effect of 5 and drug b has an effect of 8, a purely additive combination effect would be equivalent to

answer; (a) medicalized;

option d : from a warmer substance to a cooler substance

according to second law of thermodynamic, heat flows from higher to lower temperature region. heat is the transfer of energy from an object at higher temperature to an object at a lower temperature. so energy flows from warmer to colder objects.