Critical thinking!!
Comparing and Contrasting You carry
two heavy bags of groceries upstairs to your
kitchen. Will you do more work on the bags if
you carry them up one at a time? Explain.

no both remains same...

Explanation:

because the work done is given by the product of the both the masses added (m+m) Displacement

and second time when you carry the bags individually it comes out to be the same m×displacement + m×displacement

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 =