Answer:
Added Energy
Step-by-step explanation:
The temperature of a gas can increase if we add energy to heat it. This energy can be added in the form of heat, like putting the gas next to a hot souce so heat will transfer to the gas and increase the temperature. Or energy can be added in the form of mechanical work. Both heat and work are types of energy in transition and will change the intenal energy of the gas wich depend on the temperature.
If the volume of the gas is constant, the temperature can also be increased by increasing the pressure.