Answer:
All of them
Explanation:
The effect may not be real because we don't know if the results are reproducible: Peers can identify flaws in the experimental design because an experiment must have a clear design in order to be reproducible by other researchers or else they would not have scientific validity.
The treatment kills cancer cells, but it might simply be a poison that kills all cells—even normal cells: It is possible that in the design of the experiment carried out only cancer cells were used but it had not been performed in healthy cells, which would imply the possibility that the fungus kills all the cells.
Cell samples were taken from too few patients: This may be another mistake because when only a small sample is analyzed it is not certain if the fungi are the ones that kill the cancer cells or are other conditions of the analyzed patient.
The cure for scurvy, sort of
