What is the total resistance in the circuit? (include unit in answer - ohms)

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60 ohms

Explanation:

R1=30 ohms

R2=15 ohms

R3=15 ohms

It is a series connection

Let total resistance be R

R=R1 + R2 + R3

R=30+15+15

R=60

Total resistance is 60 ohms

see earlier

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 =