Moraines are caused by a. water c. acid rain b. wind d. glaciers

Moraines occur through a geomorphological process during a moving glacier. Basically, the glacier motion picks up debris such as rocks, sediments, etc. and deposits them, thus creating moraines. So, your correct choice is D. GLACIERS. 

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Moraines are parallel ridges of debris deposited along the sides of a glacier. The unconsolidated debris can be deposited on top of the glacier by frost shattering of the valley walls and/or from tributary streams flowing into the valley.

Moraines are caused by D. GLACIERS

Answer light in color; silica-rich;