a)temperature is not a measure of quantity of thermal energy in the body.
1. temperature is an indication of the amount of kinetic energy of the molecules
2. quantity of thermal energy in the body is dependant on the heat capacity or changes in state of the body.
bi) the linear part of the graph is most appropriate as the sensitivity of the thermometer would be the same througthout the range.
biii) The voltmeter indicate potential difference. Potential at A could be higher or lower than B , Hence the temperature could be higher or lower value.