to measure the time period of simple pendulum cut a piece of a string 1 metre long attach a small clay bob and to one end of the string .starting at the angle of 10 degrees allow the pendulum to swing and measure the pendulum for 20 oscillations using stopwatch

real, smaller and upside-down.   so the answer should be b.

that the claims meet official rules.

don't misinterpret the claims

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 =