Identify the biodegradable polymer from the following.

The polymer $\begin{array}{*{20}{c}} {\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,CH_3\,\,\,\,\,\,\,\,\,\,\,\,\,CH_3} \\ {\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|} \\ {{( - CH_2 - C - CH_2 - C - )}_n} \\ {\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|} \\ {\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,CH_3\,\,\,\,\,\,\,\,\,\,\,\,\,CH_3} \\ \end{array}$ is formed from which monomer unit?

Which of the following is incorrectly matched?

Identify the polymer obtained from the copolymerization of $CH_2=CH-CN$ (acrylonitrile) and $CH_2=CH-CH=CH_2$ ($1$,$3$-butadiene).

Which of the following is a condensation polymer?

Example of a biodegradable polymer pair is