As part of a project for his biology class, Alex is studying the motion of a turtle over the course of an hour. He places the turtle at the center of a
circular tank. After a few minutes, the turtle hasn't moved and Alex ends up
drifting off to sleep. When Alex wakes up at the end of the hour, the turtle is
still at the center of the tank. Which of the following can Alex conclude about
the turtle's motion during the hour?