Question

which nutrient do adult women increase to prevent bone - density loss?
iron
water
salt
calcium

Explanation:

Calcium is a crucial mineral for bone health. Adequate calcium intake helps maintain bone density. Women, especially as they age, are at risk of osteoporosis (bone - density loss). Calcium is a key nutrient in preventing this condition. Salt (sodium) in excess can lead to calcium loss through urine. Water is essential for overall body function but not directly related to preventing bone - density loss in the context of this question. Iron is important for oxygen transport (in hemoglobin) and has no direct role in bone density maintenance.

Answer:

Calcium