Answer:
Calcium is an important mineral required by our body which is responsible to build and maintain strong bones and teeth. Other function of Calcium involves blood circulation, muscle control and nerve transmission.
As calcium is not prepared by our own body we need to consume it from outer environment and it is hard to absorb required amount of calcium, there are several factors affecting calcium absorption including aging-absorption decreases with the increase in age, insufficient intake of Vitamin D, and presence of phytic acid and oxalic acid in food (plants) that inhibit absorption of calcium.
Dietary sources of calcium involves yogurt, milk, cheese, and green leafy vegetables et cetra.