John sees Linda running towards him at 11 m/s. While running, Linda throws a ball to John at 5 m/s. What is the speed of the ball as observed by John?

uranium fissions/breaks up giving out energy and neutrons

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 =