Task: Text Categorization
Input (English): In plants, this element opposes the action of potassium to close stomata while in the body, the sarcoplasmic reticulum stores and releases ions of this element. In the body this metal is typically found in the form of hydroxyapatite and the parathyroid hormone increases concentration of it in the blood. This element is also released into the blood through a process of resorption regulated by osteoclasts. In nature, this metal is found in the minerals gypsum and limestone. For 10 points, name this alkaline earth metal found in bones.
Output (English): Science