Question

When we have a factor that always causes a disease and also demonstrates that the disease cannot occur without that factor, we say that it is ____? hint: this situation does not occur in reality. necessary and sufficient necessary but not sufficient sufficient but not necessary neither sufficient nor necessary?

Answer 1

Answer: necessary and sufficient

When we have a factor, it will always cause a disease. This sentence shows that the factor is sufficient. If you have the factor, you will have the disease.
The disease cannot occur without that factor. This sentence shows that the factor is necessary. If you don't have the factor, you will not have the disease.