In some of the liverworts, there are special elongated cells called elaters that possess a helical thickening of the cell wall. As elaters lose water, they shrink longitudinally and compress the helical thickening like a spring. When the stress reaches a critical point, the compressed "spring" snaps back to its resting position, liberating hundreds of__ in all directions.

• A. Moisture particles
• B. Spores
• C. Sperm
• D. Ova