Which of the following statements about sunspots is false? a. they are areas of the sun that are "burnt out." c. they are cooler than the surrounding areas of the sun. b. they occur on the surface of the sun. d. they occur in cycles.

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 =