`Ca^(2+)` level in body is controleed by

Options

A. thyroid gland
B. parathyroid gland
C. adrenal gland
D. both a and b

Explanation

To answer the question regarding how the `Ca^(2+)` level in the body is controlled, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Identify the Glands Involved**:
- The calcium level in the body is primarily controlled by two glands: the thyroid gland and the parathyroid gland.

2. **Role of the Thyroid Gland**:
- The thyroid gland secretes a hormone known as calcitonin (also referred to as thyrocalcitonin).
- Calcitonin functions to lower the calcium levels in the blood by inhibiting the release of calcium from bones and promoting its excretion by the kidneys.

3. **Role of the Parathyroid Gland**:
- The parathyroid gland secretes parathyroid hormone (PTH).
- PTH has the opposite effect of calcitonin; it increases the calcium levels in the blood by stimulating the release of calcium from bones, increasing calcium reabsorption in the kidneys, and promoting the activation of vitamin D, which enhances intestinal absorption of calcium.

4. **Conclusion**:
- Therefore, the regulation of calcium levels in the body is a balance between the actions of calcitonin from the thyroid gland (which lowers calcium levels) and parathyroid hormone from the parathyroid gland (which raises calcium levels).
- The correct answer to the question is that both the thyroid gland and the parathyroid gland are involved in controlling calcium levels.

### Final Answer:
The `Ca^(2+)` level in the body is controlled by both the thyroid gland (through calcitonin) and the parathyroid gland (through parathyroid hormone).

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