What is a conjugated protein called if it contains a carbohydrate as a prosthetic group?

Which of the following statements is correct?

Which of the following molecules is amphoteric in nature?

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:

Where is the protein $Clupeine$ found?

Which is the most common source of protein for vegetarians in our country?