What defines gradual coastal plain stream origins?

The defining characteristics of gradual coastal plain stream origins are centered around low relief and slow flow characteristics. In coastal plain regions, the terrain is generally flat or gently sloping, which influences the way water moves through these areas. Streams originating in such regions tend to have low gradients, leading to a slower flow of water. This results in a more meandering stream pattern as opposed to a fast-moving stream that might cut deeper into the landscape.

Additionally, this slow flow allows for the accumulation of sediment, leading to the development of characteristic features such as meanders and oxbow lakes over time. The overall hydrology and geomorphology of gradual coastal plain streams are thus marked by these qualities, making low relief and slow flow characteristics central to their definition.

Other options, such as weak geomorphology and high gradient, do not accurately describe coastal plains, where the inclination is low, and the landforms are more subdued. Intermittent zones with large headcuts and rapid transitions with bedrock bottoms relate more closely to other types of stream origins found in mountainous or more geologically varied regions, not the gradual nature typical of coastal plains. Therefore, B accurately captures the essence of what characterizes these types of streams.