You are presented with the question "What requires great amounts of water to survive?" and the following answer choices: 
- a tortoise
 - leeches
 - a dolphin
 - a lizard
 - a snake
 - trout
 - mussels
 - amphibians

Now knowing that an aquatic animal requires great amounts of water to survive and dolphins are an aquatic mammal closely related to whales and porpoises, choose the best answer.


 

   a dolphin      