Riboflavin and thiamin are important for __energy___ production within cells, including nervous system cells. 3.The niacin-deficiency disease causing dermatitis pellagra 5.This vitamin can be produced in the body if enough tryptophan (an amino acid in proteins) is present 6. is one of the plant-based forms of vitamin A that must be made active in the body. 9.Thinning of bones that occurs in older age and results in serious fractures 10.Active vitamin D acts on 3 key target organs/tissues in the body to raise the blood levels. 12.Type of tissue that lines and protects the digestive tract and respiratory tract and is maintained by vitamin A 13. factor, produced in the stomach, is needed for the body to be able to absorb adequate amounts of vitamin B12. 14.Vitamin D can be produced by exposure of the skin to .

1. Energy.

2. Pellagra.

3. Niacin.

4. Beta carotene.

5. Osteoporosis.

6. Calcium.

7. Epithelial.

8. Intrinsic.

9. Sunlight.

Explanation:

1. Riboflavin and thiamin are important for energy production within cells, including nervous system cells.

2. Pellagra: the niacin-deficiency disease causing dermatitis.

3. Niacin: this vitamin can be produced in the body if enough tryptophan (an amino acid in proteins) is present.

4. Beta carotene: is one of the plant-based forms of vitamin A that must be made active in the body.

5. Osteoporosis: Thinning of bones that occurs in older age and results in serious fractures.

6. Active vitamin D acts on 3 key target organs/tissues in the body to raise the blood calcium levels.

7. Epithelial: Type of tissue that lines and protects the digestive tract and respiratory tract and is maintained by vitamin A.

8. Intrinsic factor, produced in the stomach, is needed for the body to be able to absorb adequate amounts of vitamin B12.

9. Vitamin D can be produced by exposure of the skin to sunlight.

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.

b. heterotroph

explanation: