A cylindrical rod 100 mm long and having a diameter of 10.0 mm is to be deformed using a tensile load of 27,500 N. It must not experience either plastic deformation, or a diameter reduction of more than 7.5 x 10-3 mm. Of the materials listed below, which may be used?

i need with 1.3.2 investigate cycling o2 and co2 apex

we need to see it

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 =

3. dark matter

empty space could also be a simple vacuum