An aquatic animal requires great amounts of water to survive, and dolphins are an aquatic mammal closely related to whales and porpoises. Given these facts, what requires great amounts of water to survive among the following options:
- a tortoise
 - leeches
 - a dolphin
 - a lizard
 - a snake
 - trout
 - mussels
 - amphibians


 

   a dolphin      