Alarge mass of moving ice and snow on land that covers much of a continent or large island.

The correct answer is - Continental glacier.

The continental glaciers represent a very big mass of ice that covers large area. They can be smaller, when they are referred to as ice fields, or bigger, when they are referred to as ice sheets. Until pretty recently, some 10,000 years ago, the ice sheets were so vast that were covering big portions of North America, Europe, and Asia, even creating land bridge between the Asian and North American mainland. In the present, the biggest ice sheets are on the Antarctic, and on the island of Greenland.