Answer:
thermophile.
Explanation:
A thermophile is a kind of bacteria that belongs to the Archaea Domain and they are the kind of animals that can live in a region of high or extreme temperature. There has been a research on a kind of thermophile which is known as Methanopyrus kandleri which can exist in an extreme temperature of up to 500° C.
So, if we take a look at the question again we can see that after 48 hours and at 37°C 20,000 bacteria per milliliter are already in the tube and at more higher temperature of 55°C we have 1,568,000 bacteria per milliliter which means that at higher temperature more of the bacterial is produced.
I think it’s option B
I hope it helps you
I don't know if this helps or not but you would want to know the age of the rock (absolute dating) and from there you will be able to know the age of the fossil and what caused it to die.