Answer:
waste gas he should use algae
The magnetic field<span> of a bar </span>magnet<span> is </span>strongest<span> at either pole of the </span>magnet<span>. It is equally strong at the north pole compared with the south pole. The force is weaker in the middle of the </span>magnet<span> and halfway between the pole and the center.</span>
Oxygen and selenium both have 6 valence electrons. They're in the same group hope this helps
