Identify the correct statement among the following :

<p>To clarify the statements regarding amino acids:</p> <p><p><strong>Chirality in Amino Acids</strong>: Most naturally occurring amino acids contain at least one chiral center, but there are exceptions. For example, <code>Isoleucine</code> has two chiral centers, and <code>Glycine</code> is an exception as it is optically inactive due to lacking a chiral center.</p></p> <p><p><strong>Cysteine and Dimerization</strong>: The amino acid <code>Cysteine</code> can easily undergo dimerization. This is due to its free sulfhydryl (SH) group, which can form disulfide bonds, leading to the formation of a dimer.</p></p> <p><p><strong>Carboxyl Groups in Amino Acids</strong>: <code>Glutamic acid</code> is not the only amino acid with a carboxyl group in its side chain. <code>Aspartic acid</code> also contains a carboxyl group in its side chain.</p></p> <p><p><strong>Optical Activity</strong>: While many naturally occurring amino acids are indeed optically active, <code>Glycine</code> is an exception as it does not possess a chiral center and is hence optically inactive. </p></p> <p>In summary:</p> <p><p>Not all naturally occurring amino acids are optically active (e.g., Glycine).</p></p> <p><p>Not all naturally occurring amino acids contain only one chiral center (e.g., Isoleucine has two).</p></p> <p><p>Both Glutamic acid and Aspartic acid contain side chain carboxyl groups.</p></p> <p><p>Cysteine can dimerize due to its SH group.</p></p>