Answer:
The magnetic field is generated by electric currents due to the motion of convection currents of molten iron in the Earth's outer core: these convection currents are caused by heat escaping from the core, a natural process called a geodynamo.
Answer:
Kepler's third law relates the semi-major axis of the orbit to its sidereal period. The major axis is the total length of the long axis of the elliptical orbit (from perihelion to aphelion).
Explanation:
A and C