Technician a says heater temperature may be controlled by regulating the amount of coolant flowing through the heater core. technician b says heater temperature may be controlled by regulating the amount of air flowing through the heater core. which technician is correct

Both of them are correct.

Explanation: The temperature of a heater can be controled by regulating the amout of coolant that flows into the heater core, now, this "coolant" can be different things, like water or, particular to the question, air.

So both technicains are correct in this case.

answer; i believe the answer you're looking for is (nanotechnology);