If it were not for these two men, we might not have come to understand microorganisms. these men are named

anton van leeuenhook and robert hooke
pierre bayen and carl sheele
robert boyle and robert hooke
santorio santorio and galileo galilei

If it were not for these two men, we might not have come to understand microorganisms. These men are named Anton Van Leeuenhook and Robert Hooke.

b. a lightning bug, plug of grass, and a worm

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 =