Identify which two of Koch's postulates would most likely not be fulfilled when trying to link a human virus to a particular dis
ease. Choose one or more: A. The microbe is found in all cases of the disease but is absent from healthy individuals. B. The microbe is isolated from the diseased host and grown in pure culture. C. When the microbe is introduced into a healthy, nonhuman experimental host, the same disease occurs. D. The same strain of microbe is obtained from a newly diseased host.
A) There are certain viruses that are present in both healthy and disease people.
Example: Polio virus is found in many human but it causes disesease in only 1% of human.
B) Viruses require host machinery for replication so they may not replicate in pure culture.
The postulate C is also violated, the virus may not produce disease in non-human experimental host because of inappropriate animal or vaccinated animal etc. Others exception includes, the same disease may be caused by various organisms and different organisms can also cause the same disease.
It’s red shift and blue shift, because this only occurs when the frequency of the wave is made longer or shorter due to the movement of the source relative to the observer.
