Question: where are actin filaments located in the cell
[{'answer': 'cytoskeleton', 'provenance': [{'wikipedia_id': '438944', 'title': 'Actin', 'start_paragraph_id': 2, 'start_character': 135, 'end_paragraph_id': 2, 'end_character': 147, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'contractile apparatus in muscle cells', 'provenance': [{'wikipedia_id': '438944', 'title': 'Actin', 'start_paragraph_id': 2, 'start_character': 181, 'end_paragraph_id': 2, 'end_character': 218, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '438944', 'title': 'Actin', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 491, 'bleu_score': 0.9751504244977051, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15704692861525670211}, 'section': 'Section::::Abstract.'}]}]