Final answer:
The incorrect characteristic of the coastal plain is the presence of tall mountains, as this region is predominantly flat with features like sandy beaches and port cities, and does not have tall mountains.
Step-by-step explanation:
The characteristic that is NOT true about the coastal plain is C. There are lots of tall mountains in this region. The coastal plain is defined as a region that comprises flat, low-lying land adjacent to the sea coast. In the United States, the Atlantic Coastal Plain runs along the Atlantic Ocean and the Gulf of Mexico from New England to Texas. This area is known for its shallow marine sedimentary environments, which have accumulated an abundance of mature sediment and marine fossils over time, reflecting a tectonically inactive edge of the continent since the rifting of Pangaea.
The coastal plain is predominant with features such as sandy beaches, port cities, and is largely flat, making it different from mountainous regions. Some of the well-known port cities located along the coastal plain include New York, Boston, and New Orleans. These features align with options A and B, hence they are characteristics of the coastal plain. In contrast, tall mountains are not found in this region; instead, they are representative of areas like the Appalachian Highlands.
Therefore, the presence of tall mountains is incorrect and not characteristic of the coastal plain, which is largely flat and at a low elevation, especially compared to regions nearby that do possess significant elevation such as the Appalachian Highlands.