Complex sentence: William Cumming Rose (April 4,1887--September 25,1985) was an American nutritionist whose research in the 1930s discovered threonine and determined the requirement for essential amino acids in diet.
Split into simpler sentences: William Cumming Rose (April 4,1887--September 25,1985) was an American nutritionist. He discovered the amino acid threonine and his research determined the requirement for essential amino acids in diet.