Which amino acid contains a non-polar '$R$' group?

Which bond connects Valine and Cysteine?

$S$ - Statement: The amino acid with a non-polar $R$ group is serine.
$R$ - Reason: The amino acid with a polar and uncharged $R$ group is threonine.

Which statement about protein is wrong?

Given below are two statements:
Statement $I:$ Amino acids have a property of ionizable nature of $-NH_2$ and $-COOH$ groups,hence have different structures at different $pH$.
Statement $II:$ Amino acids can exist as Zwitterionic form at acidic and basic $pH$.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which of the following is proteinaceous in nature?