A car is moving at a constant speed along a straight line. which statement is true about the forces acting on the car?

Moving at constant speed means you are not speeding up (accelerating). If you think about what a force is, according to Newton's Laws, you should be able to come a reasonable conclusion about the forces acting on the car. Newtons second law of motion is F=ma Given a=0 So summation of F=0

Then force will zero because of constant velocity the acceleration is zero