1. |
The spacecraft Pioneer-10, launched from earth, is hurtling away at great speed on a long voyage,
out across Mars, Saturn and Pluto beyond the Solar system carrying a message that there is life on
earth, in the hope that an alien civilization in an advanced stage of development may respond to
this message. If you were asked to choose one of the following elements of 'matter, which one
would best convey that there is life on earth ?
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Hydrogen |