Is it illegal for me to walk around with a concealed gun at 15 years of age or not?

yes if you have a permit and the area allows guns; no if you dont have a permit and or if the area your in allows guns.

Explanation:

it depends if you have a permit, and or if the area your walking around in permits any gun.

WHY DO YOU NEED TO KNOW THIS?(btw its common sence).

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true

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 =