In benzene, why is neither of the two given resonance structures considered to be the correct representation of the actual molecule?

Resonance in $X_2Y$ can be represented as shown in the image. The enthalpy of formation of $X_2Y$ $(X \equiv X(g) + \frac{1}{2} Y = Y(g) \rightarrow X_2Y(g))$ is $80 \ kJ \ mol^{-1}$. The magnitude of resonance energy of $X_2Y$ is $......... \ kJ \ mol^{-1}$ (nearest integer value). Given: Bond energies of $X \equiv X, X=X, Y=Y$ and $X=Y$ are $940, 410, 500$ and $602 \ kJ \ mol^{-1}$ respectively. Valence $X: 3, Y: 2$.

The $C - C$ bond length in benzene lies between a single and a double bond. The reason is:

The relative stability of the contributing structures is:

Draw the resonance structures of $CO_2$.

What will be the resonance energy of $N_2O$ from the following data: $\Delta H_f(N_2O) = 82 \ kJ \ mol^{-1}$. Bond energies of $N \equiv N$,$N = N$,$O = O$,and $N = O$ bonds are $946$,$418$,$498$,and $607 \ kJ \ mol^{-1}$ respectively.