Fill in the Blanks Space explorationOnline version Complete the sentence by Greys Narvaez 1 plants lif alien Animals or that might live on other planets are called 2 solar eight sistem Our has planet s 3 fall Gravity makes things dow n 4 Neptune explore The planet was ed in 1846 . People didn't know it existed before that tim e 5 world word Another for planet is " " 6 about The distance from the earth to the sun is 150 kilometer s