Which of the following can act as both an oxidizing and a reducing agent?

Total number of species from the following which can undergo disproportionation reaction . . . . . . .
$H_2O_2$,$ClO_3^{-}$,$P_4$,$Cl_2$,$Ag$,$Cu^{+}$,$F_2$,$NO_2$,$K^{+}$

Which species among the following does not show disproportionation reactions?

What change occurs in the oxidation state during a disproportionation reaction?

What is meant by 'disproportionation'? Give two examples of disproportionation reactions in aqueous solution.

In the following reaction,$3Br_2 + 6CO_3^{2-} + 3H_2O \rightarrow 5Br^{-} + BrO_3^- + 6HCO_3^-$,what happens to bromine?