Final answer:
The correct statements about gases are that the pressure is due to molecular collisions, not that temperature is inversely proportional to volume. The correct answer is option d.
Step-by-step explanation:
Among the options given, the true statements for gases are that: (1) the temperature of a gas is not inversely proportional to its volume, but instead, the volume of a gas is directly proportional to its temperature when pressure is held constant, according to Charles's law, and (3) the pressure of a gas is indeed due to the collisions of gas molecules within a container.
Statement (2) is incorrect as the volume of a gas is inversely proportional to the pressure in torr, following Boyle's law when the temperature is constant. Therefore, the correct answer is that the true statements for gases are (3) only, which makes option (d) the correct choice.