Final answer:
Hypocalcemia causes muscle weakness, whereas hypercalcemia causes potentially fatal muscle tetanus. This statement is true.
Step-by-step explanation:
True. Hypocalcemia, which is characterized by low blood calcium levels, can cause muscle weakness. On the other hand, hypercalcemia, which is characterized by high blood calcium levels, can lead to muscle tetanus, a potentially fatal condition. When blood calcium levels are high, calcitonin is produced and secreted, which can result in underactive muscles.