The valence of helium is 0.
Ethane
see the picture for explanation
C. Refraction. When light enters a different medium, it changes direction due to change in speed and wavelength.
That would be an amino acid. The
and -COOH is the functional group for a carboxylic acid hence AMINO ACID.
The answer is D. If you've ever had table salt before you know it's not poisonous or nearly as reactive as sodium. When the two combine, they produce a new pure substance with different properties from the original reactants.
