What step should the students take next in the investigation to increase the strength of the motor? (S8P5. c.)
A Reduce the size of the axle running through the center of the motor.
B. Increase the number of coils of wire within the two sections of the motor.
C. Decrease the voltage of the power source being used to operate the motor.
D. Place the permanent magnets and coils of wire farther apart inside the motor.

positive reinforcement? ?

option number c is the right answer.

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 =