 
 <prompt> Which of the following people no measure caloric count for animals: Carl von Voit, Frederick Hopkins, or Max Rubner? Given the previous question, write a context wey contain the answer. E fit be 1 - 20 sentences. Context: <response>: For early 20th century, Carl von Voit and Max Rubner bin measure caloric energy expenditure for different animals, using physics principles for nutrition. For 1906, Edith G. Willcock and Frederick Hopkins show say the amino acid tryptophan dey help mice well-being but e no dey guarantee their growth. For middle of twelve years wey dem dey try isolate dem, Hopkins talk for one 1906 lecture say "unsuspected dietetic factors," apart from calories, protein, and minerals, dey needed to prevent deficiency diseases. For 1907, Stephen M. Babcock and Edwin B. Hart do the single-grain experiment, wey take almost four years to complete. 