Question: what is a planets backward motion in the sky called
[{'answer': 'Apparent retrograde motion', 'provenance': [{'wikipedia_id': '48908', 'title': 'Apparent retrograde motion', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 26, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '48908', 'title': 'Apparent retrograde motion', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 254, 'bleu_score': 0.953991849837532, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8914883750743820211}, 'section': 'Section::::Abstract.'}]}]