Question: what predator is at the top of the food chain
[{'answer': 'apex predator', 'provenance': [{'wikipedia_id': '1872736', 'title': 'Apex predator', 'start_paragraph_id': 1, 'start_character': 325, 'end_paragraph_id': 1, 'end_character': 338, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]