Question

chapter 1: the nature of science: how to survive a mass extinction
1.2. develop a hypothesis from one or more observations and suggest one or more predictions based on that hypothesis.
vibrio cholera is a bacterium that causes the diarrheal disease known as cholera. in the 1800s, louis pasteur noticed that old v. cholera cells did not cause disease in chickens, whereas new v. cholera cells did cause disease. he also noticed that chickens previously inoculated with old cells could not be made sick by new v. cholera cells. based on pasteur’s observations, which of the following represents a good hypothesis?
inoculation with old v. cholera strains confer resistance to disease.
inoculation with v. cholera always leads to disease.
vibrio cholera is a pathogen.
vibrio cholera only infects old chickens.

Explanation:

Pasteur saw old V. cholera cells didn't cause disease and inoculated chickens were resistant. So, inoculation with old strains conferring resistance is a valid hypothesis.

Answer:

Inoculation with old V. cholera strains confer resistance to disease.