Please help me NO JOKING

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.

If the pressure in a gas is doubled while its volume is held constant. true or false

Abody covers a semicircle of radius 7cm in 5s .find its linear speed