I think this is the answer
Because magnesium loses its electrons easily than aluminum
Ionic compounds are compounds composed of a metal as the cation (positive charge) and non-metals as anion (negative charge). Covalent compounds are composed of both non-metals. In this respect, a) water is covalent b) covalent c) ionic d) ionic e) covalent f) ionic.
Where are the substances?
First one is cell Membrane and the second one is cell Wall