. The displacement vector A has a length of 50 m and a direction of 300 east of north;
the displacement vector B has a length of 35 m and a direction 700 west of north. What is
the magnitude and direction of A x B.

c. newton's third law of motion

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 =