Using mo theory, predict which of the following species has the longest bond and which the strongest bond, respectively: o2, o2−, o22−

MO theory stands for Molecular Orbital theory which is sued to detremine the molecule structure. The bond length in the oxygen species, O2+, O2, O2-, O2^(2-), can be explained by the positions of the electrons in this theory. 
bond order = 1/2 (#e- in bonding MO's - #e- in antibonding MO's) 
bond order for O2 is 2 
bond order for O2+ is 2.5
bond order for O2- is 1.5
bond order for O2(2-) is 1

I’d have to say no because without oxygen in the water the fish would all be dead. so if you want to fish for dead fish, pick the ponds with the lowest oxygen concentrations.

Nonmetals usually react by gaining electrons