Early scientists studying a glacier put stones on the ice surface in a straight line across the valley, and came back later to find that the line was bent and moved downhill. The scientists determined that the stones did not slide off the glacier, but were carried by the flow of the glacier. What did the scientists mean by "flow of the glacier"?

The given question is incomplete as the options are missing. The options related to this question are as follows-

(A) The weight of the stones had broken the ice into chunks that rolled downhill, like dry sand falling off an anthill.

(B) The sun’s energy had heated the rocks and caused the whole glacier to melt and flow downhill, and then the water refroze at night with the rocks still on top.

(C) Because the ice was almost warm enough to melt, the ice deformed slowly something like hot iron in a blacksmith shop or a chocolate bar in your pocket.

(D) The pressure of the stones had converted the ice to a denser, high-pressure phase, and the resulting implosion earthquake had moved the stones.

(E) The ice had relaxed, taken the day off, and gone out for pizza with its friends, dropping the stones on the way

Option (C)

Explanation:

The flow of glaciers refers to the downward moving of the glaciers under the influence of gravity, and when they move they carry particles such as stones, boulders, and rocks along with them, scratching the surface of the rocks.

As the ice or glaciers move, it creates friction, as a result of which, it gets heated up at the contacting surface. This results in the slow melting of the ice and glaciers, that is similar to the chocolate that melts when kept in a pocket, or like the hot iron melting that is commonly observed in blacksmith's shops.

This melting of ice slowly initiates the flow of glaciers along the gentle or steep slope, carrying various types of materials along with it.

Thus, the correct answer is option (C).