mary is standing at a place such that she makes an angle of 42° to the right of the normal of a mirror. where should mary's mom stand so that she can best see mary's reflection in the mirror? a) at an angle 84° to the right of the normalb) directly behind maryc) at an angle of 42° to the left of the normald) at an angle 90° with the normal

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 Mary's reflection in the mirror At an angle of 42 degrees to the left of the normal. Because the law of reflection states that the angle of incidence is equal to the angle of reflection

i believe the answer is a hope it and is correct

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 =