How is the scale of objects used when scientists create models of real world phenomenon and why is it important?

Biology 1c cumulative exam i need awsners

When coal has reached it hardest, darkest form, it is called select one: 0 a. sub-bituminous b. lignite c. bituminous d. antrhacite next page

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).