Which explains why carbon is a component of so many elements?
a. it appears in more than one form
b. it is the most abundant element
c. it can react with both metals and nonmetals
d. it can form stable compounds with other elements

If a molecule with a molecular formula of c13h18 is treated with an excess of h2 in the presence of finally divided pt metal under conditions required for maximum hydrogenation of the molecule to give a molecule with a formula c13h24, how many rings are in the molecule?