They need it to build strong bones.
It is important to a child for bone and teeth development.
Iron and calcium
Calcium plays an important role in strengthening bones and teeth. Thus it is especially important for children whose bones are growing and the elderly who may experience a loss of bone density due to loss of calcium.
Your question needs context. Why is calcium so important to what?
the calcium is important It makes your bones stronger.
There are four electrolytes that are important to heart function, potassium, calcium, sodium and magnesium. Calcium is important in the actual contraction of the heart.
Milk in an excellent source of calcium, especially for children and women. It adds calcium.
Calcium is important at every age, but many people don't get enough. Your body needs calcium to build strong bones when you're young and to keep your bones strong as you get older. Getting enough calcium is especially important for children and teens, young adults, and women after menopause.
Milk has long been regarded as an important food for children, since it's rich in calcium which has often been linked with children's growth. However the kind of growth which is said to be related to calcium intake is the growth of bones (skeletal growth) rather than the growth of breasts, and even the growth of bones in a child can only be affected by increasing calcium intake if the child is suffering from calcium deficiency.
Milk has long been regarded as an important food for children, since it's rich in calcium which has often been linked with children's growth. However the kind of growth which is said to be related to calcium intake is the growth of bones (skeletal growth) rather than the growth of breasts, and even the growth of bones in a child can only be affected by increasing calcium intake if the child is suffering from calcium deficiency.
to strengthen their bones
Dietary calcium is important to bone growth because bones are made of calcium. The addition of dietary calcium keep the bones calcified and helps them to stay strong and healthy.