Depends on what type, because Electric ones convert electricity to mechanical energy, but a Manual turn can opener you work with your hands is just straight mechanical energy. If you are talking about an Ecosystem, I am severely disappointed and you are grounded from the internet for 1 week.
D: Nonpolar covalent bonds involve two atoms that have equal electonegativity whereas polar covalent bonds involve two atoms that are unequal in their electronegativity.
