Atoms combine as the electrons from each atom are attracted to the nuclei of the atoms. This results in bonds ranging from 100% covalent to bonds with high ionic character. The combination of atoms to form compounds occurs when the compounds being formed are at lower energy than the original atoms
The answer is C.Circulatory because its made up of blood vessels that carry blood away from and towards the HEART
You that Mg is the metal if in the periodic table it lands between group 1-12. So yeas Mg is a metal because it lands in group 2.