Reading - Part 1

Read the text. Fill in each gap with ONE word. You must use a word which is somewhere in the rest of the text.

How an Island Is Formed?

Most islands are located in oceans. Many of these (1) are the tops of huge volcanoes. The volcanoes go all the way down to the bottom of the sea. But they began under the ocean floor. The ocean floor is part of a layer of Earth called the crust. It is very hot underneath the crust, so the rocks there are soft. Those hot, soft rocks rise through cracks in Earth's (2). That action is the beginning of an underwater volcano. When hot rocks rise through the crust, they hit the water. The (3) cools the rocks and hardens them. As more hot rocks spill out of the cracks, layers of rocks build up. Over a long period of time, the (4) can get higher and higher. As a result, the underwater volcano might rise out of the (5). The top of that (6) then becomes an island.