Speed of light
According to Einstein, the speed of light is constant in all points of reference. In addition, he pointed out the speed of light is the maximum speed known since in practice one can never catch up with the beam of light. This is explained by his theory of relativity.
A substance changes from liquid to gas
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We know that, acids and strong bases are good conductors of electricity!. And gold conducts electricity , while the best is silver and niext comes gold!. And H20 which is water contains less ions , so it is not a good conductors , it is a conductors but not a good conductor!. Salt in it's solid for cannot produce ions, hence, it cannot conduct electricity , but when this salt is mixed with water or when it is in it's molten state it can conduct electricity!. So now,the answer for the question is ,
B) III and IV only!.
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