When a chunk of ice left behind by a receding glacier melts, the water stays in the kettle, forming

Kettle lake

Explanation:

A kettle lake forms when a receeding glaciers leaves glacier behind in a shallow depression called a kettle.

Kettles and kettle lakes are products of glacier deposition. They are mostly attributed to the receeding phase of a glacier. The mouth of a retreating glacier are usually laden with a mix of melt water and sediments. As the glacier continues to retreat, it leaves behind stagnant ice that must have been buried with the sediment. When the ice melts, a kettle which is an hollow depression forms and the water in it makes it a kettle lake.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.