What is the acceleration down the ramp of an object on a 17° ramp? A
2.9 m/s2
B
4.2 m/s2
C
5.5 m/s2
d
9.4 m/s2

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 =