Barrier islands . a. are elongated, narrow, and sandy b. are separated from the mainland by a lagoon, bay, or estuary c. occur where sand is in plentiful supply d. occur where the sea floor is gently sloping e. All of the above are correct.

The correct answer is E, as all options are correct.

Explanation:

A barrier island is a type of coastal geological formation consisting of one or more long, narrow islands parallel to the coasts. The arm of the sea between the two thus forms a lagoon. They are constantly evolving, shaped by storms and other sea actions, but they absorb the energy of the waves, protect the coasts and create protected areas where wetlands can thrive.

The chain of islands can be extended without interruption for more than a hundred kilometers with gravel allowing the entry of the tide into the lagoon. The length and width of the barriers, as well as their morphology, are related to the amplitude of the tides, the energy of the waves, the supply of sediments, the evolution of sea level and the shape of the seabed.

The barrier island chains cover about thirteen percent of the world's coasts. These places having different characteristics, this suggests that they can form and be maintained in an infinite variety of environmental parameters.

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