Which does not represent one of koch’s postulates?

a. isolate germs from an infected animal
b. grow germs in a lab culture
c. inject germs into a healthy animal
d. watch to determine how long it takes for the healthy animal to become ill

Abird flies by moving its wings up and down. which two systems are most directly responsible for the movement of a bird's wings? a. skeletal and muscular systems b. respiratory and muscular systems c. skeletal and digestive systems d. respiratory and digestive systems