What happens when the internal energy of a material increases? . a. its temperature will rise b. it will go through a phase change c. a and b d. a or b

D. A or B
The temperature of a substance cannot increase during phase change, so both A and B cannot happen simultaneously. And internal energy is the sum of the microscopic potential and kinetic energies of a substance, which increase with temperature and phase transition. 

Gas will most likely  fill the container 

Fitness is the ability to perform only very light levels of physical activity.