many tourists visit california’s death valley national park motivated by curiosity to see a geological phenomenon known as the sailing stones or moving rocks. the sailing stones only move every few years, and they leave a trail behind them. geologists have been researching the stones since 1915, but their records indicate that there are no consistent patterns in the stones’ movements. the writer wishes to add a sentence that elaborates on the geologists’ observations of the stones’ movements. given that all the following statements are true, which one, if added after the last sentence, would most effectively accomplish the writer’s goal? some stones weigh as much as one hundred pounds and are unevenly shaped. some explanations for this phenomenon include the influence of supernatural elements and the force of strong winds. stone trails vary in length and direction, and some stones leave a straight path while others weave through the desert. according to an article published in the los angeles times in may 2013, some stones have been stolen from death valley national park.