Question: When a chicken egg was placed in a beaker of vinegar, bubbles formed on the eggshell. After twenty-four hours, the eggshell is no longer present. Which statement is an observation?

  Options: 
 A. Gravity made the egg sink to the bottom of the beaker.
 B. The vinegar caused the eggshell to dissolve.
 C. The egg was denser than the vinegar.
 D. Bubbles appeared on the eggshell. 
Answer: D