Which statement correctly describes Earth’s magnetic field lines

Protons and neutrons are found within the nucleus of an atom

Point charges q1 = 51 µc and q2 = −27 µc are placed 1.0 m apart, with q2 on the right. what is the force (in n) on a third charge q3 = 19 µc placed midway between q1 and q2? (assume the positive direction is to the right. indicate the direction with the sign of your answer.)

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3.4×106m.