\textbf{222.} Which statement is \textbf{incorrect}?
\begin{itemize}
\item[(1)] Polymers have molecules with long chains and very high molecular mass.
\item[(2)] Polyethylene is a white solid that forms at high pressure by heating ethylene.
\item[(3)] In a polyethylene molecule, each carbon atom has four separate covalent bonds with four other atoms (carbon and hydrogen).
\item[(4)] In all natural and synthetic polymers, the monomers must have double carbon–carbon bonds.
\end{itemize}