Which fuel does not produce air pollution when it burns

In a water molecule, hydrogen and oxygen are held together by a(an) bond. a) double covalent b) ionic c) nonpolar covalent d) hydrogen e) polar covalent

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?

If two objects at different te,peraure are in contact with each other what happens to their temperature