If an engine has a compression ratio of 7: 1,a. the air-and-fuel mixture in the cylinder is squeezed into a space that's seven times smaller during the compression stageb. the air-and-fuel mixture in the cylinder is squeezed into a space that's seven times larger during the compression stagec. the engine produces seven times more horsepower than it does torqued. the engine produces seven times more torque than it does horsepower

A.

Explanation:

Compression ratio of an engine is defined as the ratio of the volume of gas in cylinder when the position is at TDC ( top dead center ) means top of its stroke to the volume of the gas when piston is at the bottom which is BDC or bottom dead center.

So if an engine has a compression ratio of 7 :  1 then it means the air and fuel mixture in the cylinder is squeezed into a space that is seven times smaller during the compression stage.

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 =