Question: what is the outer layer of the nucleus called
[{'answer': 'nuclear membrane', 'provenance': [{'wikipedia_id': '6235', 'title': 'Cell nucleus', 'start_paragraph_id': 3, 'start_character': 176, 'end_paragraph_id': 3, 'end_character': 192, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6235', 'title': 'Cell nucleus', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 684, 'bleu_score': 0.9808590314834971, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5116928376929384019}, 'section': 'Section::::Structures.:Nuclear envelope and pores.\n'}]}]