Question: Estuaries are marine environments located in areas where fresh water from rivers flow into the ocean. Estuaries are one of the most biologically productive ecosystems. Birds, fish, turtles and many other organisms inhabit these ecosystems. Which will most likely cause changes to estuary habitats on a global scale?

  Options: 
 A. decreases in powerful hurricanes
 B. decreases in volcanic eruptions
 C. increases in earthquakes
 D. increases in sea level
Answer: D