2. How are the doppler effect in sound and the red-shift light similar/different?
3. Does red-shift indicate something moving toward or away from the earth? How do you
know? (Hint: doppler effect with sound)

d. air pressure decreases as altitude increases.

it was given as a lesson and guide for prayer.

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 =