How do hydrothermal vent archaea get energy?

The cluster of developing cells from conception until birth is called an

If a strand of dna has 35% thymine. what is the percentage of cytosine, adenine, guanine?

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).