What is a Weather Front​. in your own words but be more detailed about what you say.

Explanation:

A weather front is a boundary separating air masses of several characteristics eg. Air density, wind and humidity. Disturbed weather often arises from these differences

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 =