Which of the following amino acids is not optically active?

Which is an optically inactive amino acid?

The total number of amino acids present in insulin is

All of the following statements apply to proteins except

Identify the essential amino acids from below $:$
$(A)$ Valine
$(B)$ Proline
$(C)$ Lysine
$(D)$ Threonine
$(E)$ Tyrosine
Choose the correct answer from the options given below $:$

In the given pentapeptide,find out an essential amino acid $(Y)$ and the sequence present in the pentapeptide: Choose the correct answer from the options given below: