Read the text and fill in the gaps with the given words. There are two extra words you do not need to use.

How the Solar System Was Formed
The solar system was ... about 4.7 billion years ago. It probably started as a loose cloud of ... and dust. Scientists think that a force called ... pulled parts of the cloud together into clumps. The largest clump was squeezed together so tightly that it got very hot. This clump eventually became the ... . Over millions of ... , the other clumps became the planets. The Sun’s strong gravity eventually pulled the planets into their orbits. Over time some of the leftover clumps became asteroids, ... , and other small, icy objects.