Final answer:
The statement is False because a closed system can conserve momentum, adhering to the Law of Conservation of Momentum, regardless of the energy exchange with the environment.
Step-by-step explanation:
The statement 'a closed system cannot conserve momentum.' is False. A closed system can indeed exchange energy with its surroundings but not matter. However, the conservation of momentum applies to the closed system regardless of the exchange of energy, as long as no external forces are acting on it. In any interaction of a closed system of objects, the total momentum of the system is conserved (pƒ = Σƒ), which is a fundamental principle known as the Law of Conservation of Momentum. It states that in a closed system, the total momentum never changes. This is distinct from the conservation of kinetic energy, which may not be conserved in cases such as inelastic collisions.