Context: All substances are made up of small particles of matter that are constantly moving. In a gas, these particles can move freely and tend to be far from one another. In fact, the space a gas takes up is mostly empty!
Gas particles move quickly and randomly. They travel in straight lines, changing direction whenever they collide with each other or with the walls of their container. Even though there is a lot of space between particles in a gas, collisions occur frequently because the particles are moving so fast.
Which of the following statements is true about gas particles?
A. Gas particles are tightly packed together.
B. Gas particles rarely collide with each other.
C. Gas particles are always moving.
From the given choices, pick the correct answer and respond by indicating the letter of the correct option.

C