Newton's Laws vs. Conservation Principle Steps:

• Recall Newton's first law: An object remains at rest or in uniform motion unless acted on by a net force, meaning constant velocity with no resultant force.
• Recall Newton's second law: Force equals mass times acceleration (F = ma), or rate of change of momentum proportional to force and in its direction.
• Recall Newton's third law: For every action, there is an equal and opposite reaction between two bodies.
• Compare option D: It describes conservation of momentum for isolated systems, a derived principle, not one of the three laws.

Why D is correct:

• Conservation of momentum follows from Newton's laws but is not stated as one of the original three laws.

Why the others are wrong:

• A states Newton's third law of action-reaction forces.
• B states Newton's first law of inertia and constant velocity.
• C states Newton's second law relating force to momentum change.

Final answer: D