Question: which class is thought to have been descended from dinosaurs
[{'answer': 'birds', 'provenance': [{'wikipedia_id': '30600763', 'title': 'Evolution of reptiles', 'start_paragraph_id': 1, 'start_character': 324, 'end_paragraph_id': 1, 'end_character': 329, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '30600763', 'title': 'Evolution of reptiles', 'start_paragraph_id': 31, 'start_character': 0, 'end_paragraph_id': 31, 'end_character': 467, 'bleu_score': 0.9720210313175831, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4112620694486700905}, 'section': 'Section::::Rise of dinosaurs.:Bird evolution.\n'}]}]