Phil is a scientist for NASA. Scientists are always asking questions. One question Phil has is:”Are Rocks on the Earth l【1】 rocks on Mars?” The first step was to collect rocks from around the world. I【2】 of collecting the rocks himself, Phil thought of a good idea. He would ask kids everywhere to s【3】 him rocks. Soon children from all over the world have sent in over 8,000 rocks. Phil and other scientists study each rock to d【4】 what minerals(矿物质) are in it. Studying rocks from the Earth is the easier part of Phil’s project. Learning about rocks on Mars is more c【5】. To do this, Phil helped c【6】 a special camera that was sent into space. It c【7】 around Mars and takes pictures of rocks there. Scientists learn a lot by c【8】 rocks from the Earth and Mars. They learn how the Earth and Mars are d【9】, and they learn how the planets are alike, too.

Mars is the planet most like Earth. “ Studying Mars can tell us a lot about the planet and what humans have to be p【10】 for when they get there,” Phil said.