Which of the following amino acids contains sulfur?

In an alkaline medium,glycine predominantly exists as/in a/an

In the given reaction: $CH_3-CHCl-COOH \xrightarrow[(ii) H_2O]{(i) NH_3 (1 \text{ mole})} [X]$. Product $[X]$ will be:

Assertion : At isoelectric point,the amino acid does not migrate under the influence of an electric field.
Reason : At isoelectric point,amino acid exists as a zwitterion.

Which one of the following structures represents the peptide chain?

An amino acid may be represented by the general formula $H_2N-CH(R)-COOH$. If $R = -CH_2C_6H_5$,it is phenylalanine $(Phe)$,and if $R = -CH_3$,it is alanine $(Ala)$. Identify the correct reagents from the list below to synthesize the dipeptide $Phe-Ala$:
$(1) ZNH-CH(CH_3)-COOH$
$(2) H_2N-CH(CH_3)-COOCH_2C_6H_5$
$(3) ZNH-CH(CH_2C_6H_5)-COOH$
$(4) H_2N-CH(CH_2C_6H_5)-COOCH_2C_6H_5$
(Note: $Z$ represents the benzyloxycarbonyl protecting group).