Which lipid acts as a chemical messenger

What molecules will be best used to compare different species with the exact same sequence of amino acids? why would two species have the same protein even if the molecules in question is different? (hint: transcription to translation to protein).

In the ocean why are the greatest amount of primary producers found in the epipelagic zone and how does that affect biodiversity

With regard to enzymes, key is to lock as a) substrate is to activation energy eliminate b) product is to substrate. c) enzyme is to active site. d) substrate is to active site.