Which phenomenon is caused by the movement of glaciers?

The correct choice is glacial erosion, which is directly associated with the movement of glaciers. As glaciers advance and retreat over the landscape, they carry with them a vast amount of sediment and rock fragments. This process involves two main actions: the physical grinding of bedrock due to the weight and movement of the glacier and the transporting of these materials to new locations.

As glaciers move, they act like slow-moving rivers of ice, sculpting the underlying terrain, which leads to features such as U-shaped valleys, fjords, and moraines. The scouring action of the glacier adds to the mechanical weathering of rocks, breaking them down and contributing to the geological landscape.

The other phenomena listed do not relate to glacier movement. Thermal expansion pertains to the increase in volume of substances when heated, circular eddies are fluid dynamics phenomena relevant in water bodies and air currents, and tornado formation involves specific atmospheric conditions unrelated to glacial activity. Thus, glacial erosion stands out as the phenomenon directly caused by glacier movement.