Loading...
In Death Valley National Park's Racetrack Playa, a flat, dry lakebed, are 162 rocks--some weighing less than a pound but others almost 700 pounds--that move periodically from place to place, seemingly of their own volition. The ________ Racetrack-like trails in the mysterious migration.<br/><br/>Which choice completes the text so that it conforms to the conventions of Standard English?