Question: what is the process that takes place at mid ocean ridges
[{'answer': 'seafloor spreading', 'provenance': [{'wikipedia_id': '1821971', 'title': 'Mid-ocean ridge', 'start_paragraph_id': 1, 'start_character': 209, 'end_paragraph_id': 1, 'end_character': 227, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]