If the relative activities of two metals breakdown are known, which metal is more easily oxidized?

Can someone me with questions 12 and 13 plz.

If the density of water is 1.0 g/cm3, which of these materials would float in water, based on their densities? check all that apply. aluminum cork iron lead wax

Will give ! what are the advantages and disadvantages of nuclear power? check all that apply. one advantage of nuclear energy is that it does not produce carbon dioxide emissions. storage of nuclear waste is a short-term problem associated with nuclear energy. the problem with uranium mining is that a large quantity of uranium must be extracted to meet energy needs because the energy release from uranium fission is so low. safe operation of a nuclear power plant can be jeopardized by a human mistake.