An ecologist examining the leaves of a diseased plant wonders if the fungus found on its roots is the pathogenic organism. Which step would be least necessary in order for the scientist to confirm that the fungus is responsible for the disease

See the answer below

Explanation:

It seems like you forgot to include the available options in order to answer the question.

However, according to plant pathologists, in order to establish that a particular organism is responsible for a certain observable disease, certain conditions have to be fulfilled. These conditions include:

Any other condition that is short of the above-listed conditions can be considered to be least necessary in order for scientists to confirm if an organism is responsible for a particular disease.