Final answer:
The statement consistent with the kinetic-molecular theory is (b) Gases consist of particles in constant random motion, as this aligns with the theory's assumption that gas particles are always moving rapidly in random directions due to their kinetic energy.
Step-by-step explanation:
According to the kinetic-molecular theory of gases, the statement that is consistent with this theory is (b) Gases consist of particles in constant random motion. This is because one of the fundamental assumptions of the kinetic-molecular theory is that gas particles are in constant, rapid, and random motion. This movement is due to the kinetic energy they possess, which is influenced by the temperature of the gas. Therefore, other statements such as gas volume being inversely proportional to temperature or gas particles having a fixed position are incorrect and do not align with the kinetic-molecular theory.