Which of the following situations would cause the greatest decrease in the motion of molecules in a system?
a. q = -50 j, w = -50 j b. q = +50 j, w = +50 j c. q = -50 j, w = +50 j d. q = +50 j, w = -50 j

the answer would be c

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 =