Question: where is the most of the iodine in the body concentrated
[{'answer': 'thyroid gland', 'provenance': [{'wikipedia_id': '23747793', 'title': 'Iodine in biology', 'start_paragraph_id': 5, 'start_character': 461, 'end_paragraph_id': 5, 'end_character': 474, 'bleu_score': 1.0, 'section': 'Section::::Functions.:Thyroid.\n'}]}, {'provenance': [{'wikipedia_id': '23747793', 'title': 'Iodine in biology', 'start_paragraph_id': 5, 'start_character': 152, 'end_paragraph_id': 5, 'end_character': 869, 'bleu_score': 0.7447935207166191, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5529093171119050459}, 'section': 'Section::::Functions.:Thyroid.\n'}]}]