Question: where is the meridian that is opposite the prime meridian located
[{'answer': 'the 180th meridian', 'provenance': [{'wikipedia_id': '50225', 'title': 'Prime meridian', 'start_paragraph_id': 1, 'start_character': 177, 'end_paragraph_id': 1, 'end_character': 195, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'antimeridian'}, {'provenance': [{'wikipedia_id': '50225', 'title': 'Prime meridian', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14941044184057248764}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '50225', 'title': 'Prime meridian', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 452, 'bleu_score': 0.8099424905423, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14941044184057248764}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '50225', 'title': 'Prime meridian', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['A prime meridian is a meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great circle. This great circle divides a spheroid, e.g., Earth, into two hemispheres. If one uses directions of East and West from a defined prime meridian, then they can be called the Eastern Hemisphere and the Western Hemisphere.\rhighlight sentence(s) containing evidence, not only the answer', 'Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great circle. This great circle divides a spheroid', 'A prime meridian is a meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great circle']}}]}]