Question: the oligodynamic effect is a phenomenon that describes
[{'answer': 'a biocidal effect of metals', 'provenance': [{'wikipedia_id': '2095134', 'title': 'Oligodynamic effect', 'start_paragraph_id': 1, 'start_character': 74, 'end_paragraph_id': 1, 'end_character': 101, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'a biocidal effect of metals , especially heavy metals , that occurs even in low concentrations'}, {'answer': 'biocidal effect of metals , especially heavy metals'}, {'provenance': [{'wikipedia_id': '2095134', 'title': 'Oligodynamic effect', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['The oligodynamic effect (from Greek oligos "few", and dynamis "force") is a biocidal effect of metals, especially heavy metals, that occurs even in low concentrations', 'The oligodynamic effect (from Greek oligos "few", and dynamis "force") is a biocidal effect of metals, especially heavy metals, that occurs even in low concentrations.', 'a biocidal effect']}}]}]