Haemoglobin molecule is made up of

Which of the following statements is correct?

Draw the structure of the amino acid,alanine.

Which macromolecules provide protection against infectious agents?

In $L-malic$ acid and $L-lysine$,what does the $L$ represent?

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: