Question

what force causes a planet to travel along a curved path instead of moving in a straight line as in the diagram?
wind
solar radiation
gravitational attraction
magnetic force

Explanation:

Step1: Recall gravitational force concept

Gravitational force is the force of attraction between two masses.

Step2: Apply to planetary motion

Planets are in gravitational interaction with the sun. According to Newton's law of gravitation, the sun's gravitational pull on a planet causes the planet to follow a curved path (an orbit) instead of moving in a straight line (which would be the case in the absence of a net force, as per Newton's first law of motion).

Answer:

Gravitational attraction