a person tries to move a heavy stone of mass 100 kg for an hour but fails (a).How much work has to be done on the stone?(b).if instead ,he ,lifts lifts it up to a height of 2m , how much work is done

photocells convert light energy to electricity

i would say

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 =