Element reaction can someone help me

What are scientists who study fossils called? ( a ) astronomers. ( b ) biologists. ( c ) geologists. ( d ) paleontologists.

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?

What are the similarities between compounds and mixtures?