This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'An angle class II malocclusion is worsened by: \nSelect and explain. \nA. Overclosure, B. Short facial height, C. Decreased mandibular growth, D. Decreased lip activity', 'role': 'user'}, {'content': "Answer: C \nExplanation: CLINICAL SIGNIFICANCE\nAngle's Class II Division 1 Malocclusion (Distoclusion)\nMolar relation: The lower dental arch is distally positioned in relation to the upper arch. The distobuccal cusp\xa0of the upper first permanent molar occludes with the mesiobuccal groove of the lower first permanent molar.\xa0\nClass II canine relation: The distal incline of the upper\xa0canine occludes with the mesial incline of the lower canine.\nLine of occlusion: This will be altered. Other features of\xa0Class II division 1 are:\n\nV-shaped or constricted maxilla\nProclined maxillary incisors\nLip trap\nExaggerated Curve of Spee\nDeep bite\n\nClass II division 1 subdivision: This is a condition\xa0where the Class II molar relationship is unilateral or present only on one side with normal Class I molar occlusion\xa0on the other side.\nKey Concept:\xa0\nThe mandibular deficiency worsens the class II condition. In such case, treatment should aim at reducing protrusion of maxilla and in meantime augmenting the growth of mandible.", 'role': 'assistant'}]