Here's a breakdown:

* Coastal Plain:

* Low elevation: Coastal plains are generally very flat and lie at low elevations, often just above sea level.

* Gentle slopes: The land slopes very gradually towards the sea, creating a wide, flat area.

* Sedimentation: They are formed from sediment deposited by rivers, ocean currents, and wind, creating fertile soil.

* Interior:

* Higher elevation: Interiors often have higher elevations, with mountains, plateaus, and valleys.

* Varied topography: The landscape is usually much more varied with steeper slopes, hills, and canyons.

* Erosion: The interior is often shaped by erosion from rivers, glaciers, and wind, creating dramatic features.

Other differences might include:

* Climate: Coastal plains tend to have a milder climate influenced by the ocean, while interiors often experience more extreme temperatures.

* Vegetation: Coastal plains can support diverse vegetation, from forests to grasslands, while interiors might have more arid environments with different plant life.

* Population: Coastal plains are often more densely populated due to their proximity to water and fertile land.

Let me know if you have any more questions!