D, light can travel in the air or a vacuum and the speed is constant whether the light source is stationary or moving.
Nucleic acid<span> typically contain phosphorous, and nitrogen plays an important structural role in nucleic acids and proteins. The proteins, being made up a diverse set of amino acids, have, in addition to carbon, hydrogen, oxygen, and nitrogen, the elements sulfur and selenium.</span>
A. when evaluating a source for reliability, if they are talking about a product from a company that sponsors them they may not be honest, or if they are sponsored by a reliable company they can be trusted it depends what way you look at it.