Question: when did the land bridge between britain and europe disappear
[{'answer': 'around 6,500 -- 6,200 BC'}, {'provenance': [{'wikipedia_id': '8741683', 'title': 'Doggerland', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 579, 'bleu_score': 0.807461241910657, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6718800239310963326}, 'section': 'Section::::Abstract.'}]}]