There are five contour lines between 180 and 80 so...

2. 20m is the answer
Answer:
less water to power hydroelectric dams
less water delivered by viaducts
Map projections can vary on distance, scale, and shape the accuracy and strength and weaknesses depends on the distortion, if you google each type of map and the strength and weaknesses, your answers should come up, just look for and consider the variables I said
C. deltas are a result of deposition. it looks like a triangle at the mouth of a river