The cyclic alkene shown is treated with ozone and then with $\mathrm{H}{}_2\mathrm{O}{}_2$. Which structure is the product?

The compound shown is 3-methylcyclopentene. The double bond lies between C1 and C2, with the methyl on C3 next to it. Cleavage and oxidation give a carboxylic acid at each end of a five-carbon chain, and the methyl sits on the carbon next to one acid group, so the product is 2-methylpentanedioic acid. The 3-methyl isomer would need the methyl on the middle carbon.