The doctor took a throat swab of each patient and prepared cultures of each sample. How might the doctor be able to differentiate between pathogens based on the growth of the specimens over a certain period of time?

The doctor can confirm the presence of the pathogens by PCR

Explanation:

Polymerase chain reaction (PCR) is a technique widely used in molecular biology that is based on the amplification of specific DNA sequences. This technique enables to identify specific genomic sequences and therefore it can be used to differentiate between pathogens

when you rub, you also apply pressure, that pressure can urge the poop to come out. i think that when your rubbing, you also might be slightly breaking it up and that can further fill the stomach.  

the more fit you are, the faster the recovery. your heart rate drops most sharply in the first minute after you stop exercising; it should then fall about 20 beats a minute—a drop of less than 12 beats a minute is considered abnormal. this “recovery heart rate” is measured as part of an exercise stress test.