The north and South Poles of a magnetic field produced by an electromagnet will switch when the direction of changes.

the real answer is current

Explanation:

i took the test

the components of a vector are the parts of the vectors that are to each other.

b perpendicular

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 =