Answer:
conducting liquid interior and a rapidly rotating core
Step-by-step explanation:
A mechanism by which a celestial body such as Earth or a star generates a magnetic field is referred to as DYNAMO THEORY.
Developed by Walter Elsasser, a physcist, he described the process which involves the maintenance of magnetic field over a long period through a rotating, convecting, and electrically conducting fluid.
Hence, according to dynamo theory, a planetary magnetic field needs both a CINDUCTING LIQUID INTERIOR and a RAPIDLY ROTATING CORE so, as to generate a magnetic field.
Earth's powerful magnetic field is made through the relationship of the rapidly rotating inner core and conducting liquid, outer core.