The earth is one of the _______ pianets and it goes around the sun. A.sun B.suns C.suns' D.sun's

The earth is one of the _______ pianets and it goes around the sun. A.sun B.suns C.suns' D.sun's
With their help,man has known the ______(A.earth B.sun C.stars D.satellites) better than before and has done better _______(A.on B.in C.about D.with) many fields of science