Final answer:
When paddling a canoe upstream, it is best to stay near the shore where the water moves slower. When canoeing downstream, it is generally better to stay near the middle where the water moves faster.
Step-by-step explanation:
When paddling a canoe upstream, it is wisest to stay near the shore because the water near the shore moves slower due to resistance between the water and the shore and between different layers of fluid. This slower-moving water creates less force pushing against the canoe, making it easier to paddle.
On the other hand, when canoeing downstream, it is generally better to stay near the middle of the stream because the water in the center is moving faster, creating a stronger current that helps to propel the canoe forward.