I think option C is correct..hope it helps
The source of the earth's magnetic field is found in the ;LIQUID MAGNETIZED IRON IN THE CORE OF THE EARTH. The earth's magnetic field is believed to be generated very deep down in the earth's core as a result of molten iron which it contains.
Do u know Chinese ?if yes I can explain to u easily
The thin atmosphere of Mars is thought to be due to the planet's lack of a magnetic field, which has allowed the Solar wind to blow away much of the gas the planet once had. Venus, despite still having a thick atmosphere of CO2, surprisingly has a similar problem
...a nerve. These send signals from the body to the brain and vice versa.