You have 2 groups of elements: a. Group 1: silicon, phosphorus, and sulfur (Si, P, S) b. Group 2: oxygen, sulfur, and selenium (O, S, Se) Which of these two groups would you expect to be more similar in terms of properties? Explain why.

i think it would be 5

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 =