(a) Find response of the underdamped spring-mass system excited by step force F0. Use convolution integral and complex algebra.
(b) Find steady state value of the response.
(c) Write down a limit of the response in case  is zero.
(d) Write down convolution integrals for step force function for critically damped and overdamped systems.

see earlier answer

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 =