Answer:
it's A endothermic its when two objects rub each other to form heat this is also known as friction force
The chemical property of mercury is that it reacts with oxygen
The sample with the lowest AVERAGE kinetic energy is
the coolest one.
The sample with the lowest TOTAL kinetic energy depends on
not only the temperature of the samples, but also on their size,
since each molecule in the sample has kinetic energy.