39.2 The distance between the midpoints ot two metal balls, P and Q, respectively of masses 55 and 70 kg. is 80 cm 80 cm 55 koP) 70 kg 39.2.1 Calculate the gravitational force that P exerts on Q

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 =