Scientists have been puzzled for decades by how turtles manage to navigate across the Atlantic — but now they know. The creatures have their own inbuilt magnetic compass. A laboratory experiment has revealed that the tiny turtles are born with the ability to "detect" the magnetic fields which help them to navigate the 8,000 miles across the stormy Atlantic Ocean and back home again. After hatching from eggs laid in nests along beaches in Florida, baby turtles swim out into this current and flow with it for years, nudged along by warm waters rich in food. They seem to use both the intensity and direction of the magnetic field to navigate. It is also found that turtles born in the Pacific are genetically imprinted with a different magnetic map for currents from those in the Atlantic. They would soon perish in the Atlantic. Scientists didn’t know decades of years ago that ______.
A. turtles have their own inbuilt magnetic compass B. what kind of compass is built in turtles’ body C. what kind of map turtles use in navigating D. why turtles don’t die in the Atlantic