单项选择题

下列哪一项不属于常量元素

A．钙
B．磷
C．锌
D．钠

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单项选择题

A 38-year-old man has had headaches and nausea for the past 2 months. Laboratory findings show hypercalcemia and hypophosphatemia and normal serum albumin. Urine microscopic analysis shows deposition of calcium salts in the renal tubular epithelium. Which of the following processes has most likely produced this change in the kidney?
A、Renal tubular atrophy
B、Metastatic calcification
C、Dystrophic calcification
D、Apoptosis

单项选择题

The necessary and sufficient condition for phenomenon similarity is （）.
A. the second similarity theorem

B. The First Theorem of Similarity

C. Dimensional analysis

D. The Third Similarity Theorem