Discoveries in physics added to the anxiety of the 1920s and 1930s because they:
A. caused a majority of the population to turn to atheism.
B. proved that heaven, for purely scientific reasons, did not exist.
C. called into question established notions of truth.
D. suggested the universe was a very unstable and dangerous place.
E. answered all major questions and eliminated blind faith as a legitimate option.

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 =