What are 3 challenges Polar Bears must overcome to survive

How many species of living things are alive on earth today? more than 1,000,000 none of these answers are correct 100-500 1,000 –500,000 o 500,000 -1,000,000

(99 points) be serious! how do farts work? how do you fart without it stinking? serious answers only

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).