A basic protein contains more basic amino acids such as ______.

Basic proteins are rich in basic amino acids, which have positively charged side chains at physiological pH.

The standard basic amino acids are arginine, lysine, and histidine.

Among the given options, arginine and lysine are both basic amino acids. Methionine and valine are neutral, non-polar amino acids.

Histones are a well-known example of basic proteins, which are rich in arginine and lysine residues.

Answer: Arginine and lysine