(1) predator-prey is the most important type of ecological relationship.
true false
(2) symbiosis means "living together."
true false
(3) relationships among organisms have evolved for millions of years.
true false

the correct choice is a .

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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 =

2b2t

explanation:

2b2t