1. The human shoulder joint is an example of a ball and socket joint.

2. In this type of joint, a rounded end of one bone fits into a flat or cup-shaped recess of the other bone.

1. Decrease in bone density and strength is called osteoporosis.

2. Osteoporosis is a condition in which bones become weak and brittle.

3. Women suffer from osteoporosis more often than men.

The small intestine is the part of the digestive system that receives secretions from the liver and pancreas.

1. Rickets occurs when a child's growing bones do not develop due to vitamin D deficiency.

2. Vitamin D is an essential nutrient that helps in the absorption of calcium and phosphate.

3. Symptoms of rickets include.

- Pain and tenderness in the bones of the feet and hands

- curvature in the bones of the legs

- pain in shoulders and hips

- muscle weakness

1. There are three types of blood cells made by the bone marrow: red blood cells, white blood cells, and platelets.

2. Red blood cells carry oxygen and carbon dioxide around the body. White blood cells fight infection. Platelets help form blood clots.

3. Bone marrow is a tissue located in the hollow interior of long bones.