**Question:** A diet deficient in calcium will result in:

A. Increased calcification of soft tissues
B. Decreased calcification of bones and teeth
C. Increased absorption of calcium from the intestines
D. Decreased calcification of bones and teeth

**Core Concept:** Calcium is an essential mineral for maintaining bone health and proper physiological functions in the human body. It plays a crucial role in various physiological processes, including muscle contraction, nerve transmission, blood clotting, and maintaining the integrity of cell membranes. Calcium homeostasis is regulated by the parathyroid hormone (PTH), calcitonin, and vitamin D.

**Why the Correct Answer is Right:** A diet deficient in calcium will lead to a decrease in calcium levels in the blood, causing the body's mechanisms to compensate for this deficiency. Calcitonin is released, which lowers blood calcium levels by promoting calcium absorption in the gut and stimulating calcium deposition in bones and teeth. As a result, the correct answer is D: Decreased calcification of bones and teeth, as the body will redirect calcium to bone deposition to maintain overall calcium homeostasis.

**Why Each Wrong Option is Incorrect:**

A. Increased calcification of soft tissues: Calcium deficiency does not lead to increased calcification in soft tissues. Instead, the body will prioritize calcium deposition in bones and teeth as mentioned above.

B. Decreased calcification of bones and teeth: This answer is incorrect because the body will actually increase bone and tooth calcification to maintain calcium homeostasis.

C. Increased absorption of calcium from the intestines: Although vitamin D is crucial for calcium absorption, a calcium deficiency will not lead to increased calcium absorption from the gut. The body will prioritize bone deposition as described above.

**Clinical Pearl:** Maintaining a balanced diet rich in calcium is essential for optimal bone health and preventing disorders like osteoporosis and rickets in children. Adequate calcium intake ensures proper bone development, mineralization, and strength.