A reaction occurs in which carbon combines with oxygen to form carbon dioxide. Is this a chemical reaction or a nuclear reaction, and how do you know? A. This is a chemical reaction because only the electrons were rearranged.
B. This is a nuclear reaction, because mass was conserved
C. This is a nuclear reaction because the atoms nuclei changed.
D. This is a chemical reaction because some of the mass was not conserved​

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 chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?

Ahorizontal force of 400.0 n is required to pull a 1760 n truck across the floor at a constant speed. find the coefficient of sliding friction.