Question: species with different arrangements of atoms but having no structural differences
[{'answer': 'isomer', 'provenance': [{'wikipedia_id': '20648024', 'title': 'Isomer', 'start_paragraph_id': 1, 'start_character': 14, 'end_paragraph_id': 1, 'end_character': 20, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]