Physics help, please? :)
3. Consider a locomotive and the rest of a freight train to be a single object. Suppose the locomotive is pulling the train up a hill. Describe the action and reaction forces that cause the locomotive to move up the hill, such as the reaction force and gravity.
4. Is the force of the earth’s gravity on the sun stronger, weaker, or the same as the force of the sun’s gravity on the earth? Explain why the sun’s attraction affects the motion of the earth more than the earth’s attraction affects the sun’s motion. Employ Newton’s second and third laws in your answer.
If anyone could help me at all, with either question it would be greatly appreciated, Physics is my hardest subject, and I struggle with it.

3. Newton’s third law explains how every action has an equal but opposite reaction, meaning that forces comes in pairs. While the locomotive’s wheels are pushing back against the ground as the action force, the ground is producing a reaction force towards the locomotive, propelling it forward. Another pair of forces that act on the locomotive is gravity and normal force. While gravity is pulling the locomotive towards the ground, the normal force the ground exerts on the locomotive is why the locomotive doesn’t fall through the ground.

4. The force of Earth’s gravity on the Sun is weaker than the force of the Sun’s gravity on Earth. The Sun’s attraction affects the motion of Earth more than the Earth’s attraction affects the Sun’s motion because according to Newton’s second law, force has mass as one of its factors. The Sun has a significantly higher mass than Earth, meaning that its force of gravity would also be significantly higher. Newton’s third law is why the Earth doesn’t get marginally closer to the Sun, stating that every action has an equal and opposite reaction. As the Sun is pulling Earth towards itself, Earth is pulling away from the Sun.