Final answer:
The difference in the depths of the two coral reefs is 7 feet, obtained by subtracting the shallower depth from the deeper depth.
Step-by-step explanation:
To find the difference in the depths of two coral reefs, one being 19 feet below sea level and another being 26 feet below sea level, we simply need to subtract the two values. The difference in depth is calculated by taking the deeper reef's depth and subtracting the shallower reef's depth: 26 feet - 19 feet = 7 feet. Thus, the difference in the depths of the two reefs is 7 feet.