Which of the following statements explains why the earth has a gravitational field? a. it has mass. b. it has an electric charge. c. it is revolving around the sun. d. it is rotating on its axis.

The case of the gravity force between 2 bodies is according to Newton's law for gravity

Then, the gravitational field of the earth is cased by the mass of the earth.

The electric charge cased the electric field around the earth according to Coulomb's law.

The revolving around the sun and the rotation on its axis save the earth on its orbit around the sun and cased the 4 seasons change and the day-night change.

the higher the current the higher the mag field around it the higher the influence on the compass