[ 147 ] Earth and Space Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Why was Pluto reclassified as not a planet? When helium fuel runs out, the core of a star will expand and cool, and the upper layers will expand and eject material that will collect around the dying star to form a _________. A. black hole B. red giant C. planetary nebula D. protostar Near the end of its life, the radius of a star increases to become a _________. A. black hole B. red giant C. planetary nebula D. protostar