When placed at the perimeter of a maze with food in the center, the plasmodial slime mold Physarum polycephalum explores the maze, retracts branches from dead-end corridors, and then grows exclusively along the shortest path possible to the food. How does Physarum do this? One theory is that it leaves behind slime deposits—an externalized “memory” that “reminds” it not to retry dead ends. Which of the following best describes movement in Physarum? a. Cilia propel the slime mold. b. Flagella propel the slime mold. c. The slime mold moves by amoeboid motion. d. The slime mold moves by gliding motility.