Final answer:
The input must exceed the output for a glacier to advance. The glacier on land would cause the greatest increase in the lake's water level when melted, as an iceberg's melting does not alter the water level due to displacement.
Step-by-step explanation:
When a glacier is advancing, the input must exceed (be higher than) the output. This is because a glacier advances when more snow accumulates at its source than melts or sublimates at its edges. The excess snow compacts and turns into ice, causing the glacier to grow and move forward, or advance.
Regarding the question about the iceberg and the glacier near the North Pole: When considering which ice chunk would give the greatest increase in the level of the lake water if melted, we must consider the principle of Archimedes' Law. An iceberg floating in a lake displaces water equal to its own weight, so when it melts, the water level does not increase. On the other hand, a glacier on land contributes additional water to the lake when it melts.
Therefore, the glacier sitting on land would give the greatest increase in the level of the lake water, since all the water that results from the glacier's melting will go into the lake, whereas the melting iceberg would not increase the lake's water level because it has already displaced the water equivalent to its mass.