Question: gray matter of the spinal cord is mostly composed of
[{'answer': 'neuronal cell bodies', 'provenance': [{'wikipedia_id': '37592', 'title': 'Grey matter', 'start_paragraph_id': 1, 'start_character': 95, 'end_paragraph_id': 1, 'end_character': 115, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '37592', 'title': 'Grey matter', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 730, 'bleu_score': 0.9591116223104591, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 445012065245267877}, 'section': 'Section::::Abstract.'}]}]