Compare and contrast the features of a river near its source and far down along its course.

is fast moving and flows on a steep mountain slope. It rapidly erodes a V-shaped, steep-sided valley. Its course may include waterfalls and rapids.

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Explanation:

It comes to life in a simple and modest way , nevertheless during its course along forests, deserts and mountains  many others join it shapping and enriching its body along the way. After sometime the river becomes very different from its beginning, in some cases they get the thiner they can or even desappear comming back to life after some kilometers.

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.