What type of peptide is glycylalanine?

Which of the following statements about $\alpha$-amino acids of proteins is incorrect?

Which of the following statements correctly describes the migration aptitude of aspartic acid during electrophoresis?
$(pK_1 = 2.0, pK_2 = 3.90, pK_3 = 10.0)$
$HOOC-CH_2-CH(NH_2)-COOH$

Which among the following is a source of wool?

What is the correct order of acidity for the positions $(X)$,$(Y)$,and $(Z)$ in the given compound?

$A$ protein undergoes reversible thermal denaturation from its initial state $N$ to denatured state $D$ according to $N \rightleftharpoons D$. At $60 ^\circ C$, the concentrations of both $N$ and $D$ are equal at equilibrium, and the standard enthalpy change of denaturation is $666 \text{ kJ mol}^{-1}$. The standard entropy change ($\Delta S^\circ$ in $\text{kJ K}^{-1} \text{mol}^{-1}$) of the protein upon denaturation at $60 ^\circ C$ is closest to