Question

coastlines the boundary between the land and the ocean or a lake is the coastline. among the 50 states, the mainland of alaska has the longest coastline at 10,686 kilometers. the mainland of florida has the second longest coastline, measuring 2,170 kilometers. dunes the land that extends from a coastline may be rocky cliffs, sandy beaches, or dunes. a dune is a hill of sand piled up by the wind. dunes in the coastal regions are parallel to the coastline and protect the land from ocean waves. rivers and deltas a river is a natural stream of water that flows into another body of water such as an ocean, lake, or another river. when a river reaches an ocean, the water slows and sand, clay, and sediment in the water sink. when the sediment builds up, it makes a landform called a delta. in florida, the apalachicola river supplies sand to st. vincent’s island, a barrier island and wildlife refuge. reading check compare and contrast how are dunes and deltas similar and different?

Explanation:

Similarity:

Both dunes and deltas are coastal landforms created by the deposition of sediment (sand for dunes, sand/clay/sediment for deltas) and serve to protect coastal land areas.

Differences:

• Formation cause: Dunes are piled up by wind; deltas form when river water slows and drops sediment as it meets an ocean/lake.
• Sediment source: Dunes use wind-carried sand; deltas use sediment transported by rivers.
• Orientation: Dunes run parallel to coastlines; deltas form at river mouths extending into bodies of water.

Answer:

Similarities:

• Both are coastal landforms made of deposited sediment.
• Both protect coastal land areas.

Differences:

• Formation: Dunes are wind-formed sand hills; deltas form from river-deposited sediment at ocean/lake entry points.
• Sediment transport: Dunes rely on wind; deltas rely on river currents.
• Position: Dunes lie parallel to coastlines; deltas extend into large bodies of water from river mouths.