Answer:
It is a fact that there are nine essential amino acids, which are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
However, he needs to add at least twelve essential amino-acids to the culture for the cells to survive. They are: arginine, cystine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, histidine, tyrosine and valine.