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. 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. 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.

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. Which is a special excretory cell found in Platyhelminthes which acts like a kidney, and the flame cell does the work of removing waste material through filtration?

1. Mercury poisoning is responsible for which of the following diseases called 'Mad Hatter's Disease'?

2. Mad Hatter's Disease is a form of mercury poisoning that affects the brain and nervous system.

3. There is a risk of mental and behavioural changes, such as confusion, hallucination, and irritability etc. in this disease.

1. Rickets is a bone disease caused by vitamin D deficiency.

2. Due to rickets, the absorption of calcium and phosphorus in the bones decreases.

3. The solution to protect exclusively breastfed babies from this disease is Vitamin D supplements.

1. Explain the structure and reproductive system of algae in 1935. It was from F.  E. Fritch.

2. The study of algae is known as phycology. It is also known as Algology.

3. Algae are largely aquatic (both fresh and sea water) organisms, which are chlorophyll bearing, simple, thalloid and autotrophic in nature.