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. The smallest bone in the human body is the stapes.

2. This bone is located in the middle ear.

3. The length of the stapes is about 3 millimeters.

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.

1. Plants in the Thallophyta group are commonly called algae.

2. Thallophyta group includes such plants which are produced without embryo.

3. This group includes algae and fungi. Other plants are included in Embryophyta.

4. Pteridophyta includes plants with vascular tissue.

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. 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.