Final answer:
Based on the information provided, the question deals with coastal erosion and sediment deposition influenced by sea-level changes, affecting the U.S. coastline's erosion patterns. Coastal changes are complex and vary regionally, with gently sloping coastlines being more susceptible to erosion.
Step-by-step explanation:
The question presented appears to be concerned with coastal erosion and sediment deposition along the U.S. coastline. Based on the references given, one can deduce that sea-level changes influence the way in which sediments are deposited. With sea levels rising, transgression leads to sediment being deposited towards the coastline, while with sea levels falling, regression results in sediment being deposited away from the coastline. Erosion can be more significant where the coastline is gently sloping, such as the Southeastern United States; this region is therefore more susceptible to land area loss. The Mid-Atlantic states, on the other hand, have a steeper geography, which may provide some protection against such losses.
Given the information about how erosion and sediment deposition work, the statement that “The east and west coasts are losing sand, but the north and south coasts are stable.” seems plausible; however, without the actual map, it is difficult to determine the accuracy of this claim. The dynamics of coastline changes are complex and reliant on local geography, sediment supply, and sea-level changes. It is therefore essential to consider regional differences when evaluating coastal changes.