Kenneth and catherine lohmann of the university of north carolina explored the orientation or direction-finding abilities of loggerhead sea turtle hatchlings under varying magnetic conditions. hatchlings were placed in a tank of water in a laboratory either in a natural magnetic field of the earth or in a reversed magnetic field in which north and south were flipped. the researchers then measured the direction that the hatchlings swam. the experiments were carried out in the dark and at night since that is when most newly hatched turtles migrate from their sandy nests into the ocean.
what is the variable being tested in this experiment?
a) time of hatching
b) time of day
c) magnetic field
d) amount of light