Which of the following amino acids is basic in nature?

The number of essential and non-essential amino acids from the following list respectively is:
Val,Gly,Leu,Lys,Pro,Ser

Consider the following statements:
Statement-$I$: The primary structure of a protein represents its amino acid sequence.
Statement-$II$: The $\alpha$-helix and $\beta$-pleated sheet structures of a protein represent its tertiary structure.

Which of the following gives a positive test with ninhydrin?

The protein that is a structural material is

Lysine is least soluble in water in the $pH$ range: