Question: what is the measurement of low or high sound called
[{'answer': 'Pitch', 'provenance': [{'wikipedia_id': '18994087', 'title': 'Sound', 'start_paragraph_id': 52, 'start_character': 11, 'end_paragraph_id': 52, 'end_character': 16, 'bleu_score': 1.0, 'section': 'Section::::Perception of sound.\n'}]}, {'provenance': [{'wikipedia_id': '18994087', 'title': 'Sound', 'start_paragraph_id': 53, 'start_character': 0, 'end_paragraph_id': 53, 'end_character': 1204, 'bleu_score': 0.9761989713904581, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16136753489540102796}, 'section': 'Section::::Perception of sound.:Pitch.\n'}]}]