Which phrase describes how scientists define a system?

If a substance is not at its melting or boiling point, as the heat content of a sample of matter increases, its temperature increases the number of intermolecular bonds decreases the space between particles increases the particles move faster

Particle model to predict what will happen if a sharp object creates a hole in the soccer ball

What happens to the average kinetic energy of a gas when the particles of the gas collide against each other at a constant temperature and volume? explain your answer.