Answer:
below sea level;
-100 feets
Explanation:
Given that:
Dallas, Texas elevation = 200 feets
Jacksonville = 300 feets less than elevation of Dallas
Hence, elevation of Jacksonville :
Dallas elevation - 300 feets
200 feets - 300 feets = - 100 feets
Hence Elevation of Jacksonville city is - 100 feets
-100 feets, means elevation of Jacksonville city is below sea level (elevation points less than 0, are below sea level).