Haemoglobin molecule is made up of

An example of a phosphoprotein is .....

The formation of protein is considered as:

Which is the most abundant protein in the animal kingdom?

Which of the following statements are correct regarding amino acids?
$A$. They are substituted methanes.
$B$. Serine is an aromatic amino acid.
$C$. Valine is a neutral amino acid.
$D$. Lysine is an acidic amino acid.
Choose the correct answer from the options given below:

$A$: The polypeptide coil of collagen helix is strengthened by the establishment of hydrogen bonds between the $>NH$ group of the glycine residue of each strand and the $-CO$ group of the other two strands.
$R$: In the collagen helix,a locking effect also occurs with the help of proline and hydroxyproline amino acids.