**Core Concept**
The recommended daily intake of calcium for adult non-pregnant females is a critical aspect of maintaining bone health, preventing osteoporosis, and supporting overall bodily functions. Calcium plays a vital role in muscle contraction, nerve function, and blood clotting, and is essential for bone mineralization and density.

**Why the Correct Answer is Right**
Adult non-pregnant females require 1,000 milligrams of calcium per day, as recommended by the National Institutes of Health (NIH). This daily intake is crucial for maintaining bone density, preventing osteoporosis, and supporting overall bone health. Calcium is absorbed in the small intestine through a process involving the enzyme calcium-dependent ATPase and the vitamin D-regulated calcium-binding protein calbindin.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specify the correct daily intake of calcium for adult non-pregnant females.
**Option B:** This option is incorrect as it is the recommended daily intake for pregnant and lactating women.
**Option C:** This option is incorrect as it is the recommended daily intake for adult men.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the recommended daily intake of calcium may vary based on age, sex, and other factors, and that calcium supplements should only be taken under the guidance of a healthcare provider.

**Correct Answer: D. 1,000 milligrams.**