Assertion: Proteins are amphoteric.
Reason: They can form salts with both cations and anions.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for
Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

Hint: Proteins are huge, complex molecules that play several important roles in the human body. They are essential for the structure, function, and control of the body's tissues and organs, and they do the majority of their work in cells. Proteins are composed of hundreds or thousands of tinier units recognized as amino acids that are tied in lengthy chains. A protein is made up of \[20\] different types of amino acids that can be mixed in various ways.

Complete explanation:
Option A: Amphoteric characteristics refer to the presence of free carboxyl and amino groups at the end of a protein that can react with acids and bases. Protein has positive charges at the amino group in acidic media and negative charges at the carboxylic group in alkaline media.
Hence, option A is correct.
Option B: Proteins are considered amphoteric. This is because they can form salts with anion and cations. As a result, both the statement and the reason are true, and the reason is the correct explanation for the assertion.
Hence, option B is incorrect.
Option C: Proteins can form salts with anions and cations. This is why they are considered amphoteric. So, the statement in the reason is correct as well as the assertion.
Hence, option C is incorrect.
Option D: Proteins are referred to as amphoteric. This is due to their ability to form a salt with anion and cations. As a result, both the statement and the justification are true, and the reason is the right explanation for the assertion.
Hence, option D is incorrect.

Hence, Option A is the correct answer.

Note:
A polypeptide is a linear sequence of amino acid residues. At least one long polypeptide can be found in a protein. Short polypeptides (less than \[20-30\] residues) are generally referred to as peptides or oligopeptides and are rarely considered proteins. Peptide bonds and neighboring amino acid residues bind the individual amino acid residues together. A gene's number, which is encoded in the genetic code, determines the amino acid residue sequence in a protein.