Multiple choice general knowledge science & technology How many essential amino acids does human boday requires? 20 12 9 7 Reveal answer Fill a bubble to check yourself C Correct answer Explanation Humans require 9 essential amino acids that cannot be synthesized by the body and must be obtained from diet: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. The other numbers are incorrect.