Question: what layer of earth do convection currents occur
[{'answer': 'asthenosphere', 'provenance': [{'wikipedia_id': '7604906', 'title': 'Mantle convection', 'start_paragraph_id': 2, 'start_character': 47, 'end_paragraph_id': 2, 'end_character': 60, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '7604906', 'title': 'Mantle convection', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 611, 'bleu_score': 0.7096079164011591, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7670379920573820518}, 'section': 'Section::::Abstract.'}]}]