Why do microbiologists often disinfect work areas before working with bacterial cultures?

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).

1. seamount a raised footwall block between normal fault creates this 2. syncline break between rocks where a hanging wall rises relative to a footwall 3. hot spring on rolling hills, this a dip between hills 4. volcanic neck created when a block with hanging walls slips down between normal faults 5. caldera underwater volcano that never reaches above sea level 6. horst natural hot water on earth's surface containing many minerals 7. graben underwater volcano whose top is eroded flat by waves 8. crater less than a mile in diameter; looks like a bowl at the top of a volcano 9. guyot magma that filled the central vent that remains after the volcano has eroded 10. reverse fault over 1 mile in diameter; looks like a bowl over a volcano

What substance is the most acidic. lemon juice. tomato juice. sodium hydroxide. water