1 Only three countries in the world do not use the metric system for making measurements:
Liberia, Myanmar, and the United States. whats the meter based on?

i really dont know but i will try okay.

so i think u would just add all them up and get your answer..

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 =