On this map of Florida, the area in the black box is known as the Florida Keys. The Florida Keys are an example of what geographic feature?

Geologically, the Florida Keys are made up of the main exposed parts of coral reefs. Some of the islands have been exposed for so long that sand has built up around them, creating barrier islands, while other smaller islands remain as coral atolls.

Explanation:

places of higher salinity. there are parts of the ocean where hardly any rain falls but warm dry winds cause lots of evaporation. this evaporation removes water – when water vapour rises into the atmosphere, it leaves the salt behind, so the salinity of the seawater increases. this causes the seawater to become denser.