The histone proteins are among the most slowly evolving proteins. For example, a histone protein called histone H4 in cows and peas differs by only 2 amino acids among a total of about 100. A reason why histone proteins evolve so slowly is their function: These proteins bind with the negatively charged phosphate groups in double-stranded DNA, so the proteins must be rich in the basic amino acids lysine and arginine. Therefore, these amino acids cannot be replaced without disrupting the histone's structure and function. a. true
b. false