How are the magnetic field lines near the south pole of a magnet affected when a second south pole is brought near it? The field lines combine with the lines around the second south pole. The field lines overlap with the lines from the second south pole. The field lines bend toward the second south pole. The field lines bend away from the second south pole.

The field lines bend away from the second south pole.

Explanation:  The field lines go out of Earth near Antarctica, enter Earth in northern Canada, and are not aligned with the geographic poles.

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 =