30. (a) calculate the rate of heat conduction through house walls that are 13.0 cm thick and that have an average thermal conductivity twice that of glass wool. assume there are no windows or doors. the surface area of the walls is 120m2 and their inside surface is at 18.0ºc, while their outside surface is at 5.00ºc. (b) how many 1-kw room heaters would be needed to balance the heat transfer due to conduction?

i think the answer is tomato juice? not entirely sure though

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 =