Fthe aluminum block is initially at 25 ∘c, what is the final temperature of the block after the evaporation of the alcohol? assume that the heat required for the vaporization of the alcohol comes only from the aluminum block and that the alcohol vaporizes at 25 ∘c. the heat of vaporization of the alcohol at 25 ∘c is 45.4 kj/mol

it is given that trillions of microbes make up to 1% to 3% of the body mass.

let's take average of this percentage: 2%

consider the average mass of the human body as 70 kg.

then, trillions of microbes would have mass  

therefore, 100 trillion micro-organisms would weigh:

this is an approximate value and could change depending on the mass of the human body and percentage of the microbes present in it.

average mass per microorganism =

the answer you are looking for is d. there are no holes for blood to enter or leave the system. your welcome