challenge: What did analysis of Moby Doll's urine suggest about how whales obtain water?
  
  A. Whales drink freshwater from the surface of the ocean
  B. Whales obtain water from food and metabolism, but also drink seawater
  C. Whales obtain water from food and metabolism and do not drink seawater
  D. Whales can only obtain water from drinking seawater
  Answer: 