During a game of lazer tag, a player shoots a beam of light at a mirror and hits an opponent who is to her right on the opposite side of a wall. which wave interaction allowed her to hit her target 1. diffraction 2refraction 3polarization 4 reflection

You gave it away as soon as you told us that he used a MIRROR.

A mirror can't diffract, refract, or polarize a beam of light, or a beam of any other kind of electromagnetic radiation. The only thing on the list that a mirror can do to a laser beam is reflect. So the correct choice is 4 .

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 =