Which term refers to the section of the river found closest to the mouth, where the river is widest and flows fastest?

Which term refers to the section of the river found closest to the mouth, where the river is widest and flows fastest?

• A. Mouth
• B. Alluvium
• C. Lower Course
• D. Source

Answer: (C)

In the downstream progression of a river, the section closest to the sea is the lower course. This part is where the channel has become the widest and the valley broader, shaped by continued lateral erosion and deposition of sediments. The gradient is gentle here, so the river tends to spread out and often slows down, forming wide floodplains as it approaches the mouth. Since the description emphasizes being near the mouth and wide, the lower course is the best fit. The other terms describe different things—the mouth is the opening at the end of the river, the source is where the river begins, and alluvium refers to sediment deposited by the river.

In the downstream progression of a river, the section closest to the sea is the lower course. This part is where the channel has become the widest and the valley broader, shaped by continued lateral erosion and deposition of sediments. The gradient is gentle here, so the river tends to spread out and often slows down, forming wide floodplains as it approaches the mouth. Since the description emphasizes being near the mouth and wide, the lower course is the best fit. The other terms describe different things—the mouth is the opening at the end of the river, the source is where the river begins, and alluvium refers to sediment deposited by the river.