Which of the following statements are correct?
A) $\alpha$ - amino acids present in protein is L- amino acid.
B) Amino acids contain $\text{NH}_2$ as well as COOH group.
C) Number of amino group and carboxylic group are same in amino acids always.
D) Tryosine was firstly obtained from cheese.
Choose the correct alternatives from below:

During denaturation, which level of protein structure remains unchanged?

Identify the natural source of ascorbic acid from following.

Identify the monomers used to prepare bakelite from the following.