Final answer:
As a river ages, it may slow down, carry more water, and its floodplain may expand.
Step-by-step explanation:
As a river ages, several changes occur. First, the river may slow down as the gradient decreases. This means that the river becomes less steep and the water flows with less force. Second, the river may carry more water as it receives water from tributaries along its course. This can cause the river to widen and deepen. Lastly, as the river ages, its floodplain may expand rather than shrink. This is because the river erodes its banks and deposits sediment on the floodplain, creating a wider area for the river to flow during floods.
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