Human Body and Health: Quick Revision for Everyday Science
The human body facts most asked in Everyday Science papers: organs, bones, blood, hormones, vitamins and deficiency diseases, and common infections, in quick tables.
By the World MCQ Forum Editorial Team · 27 October 2026 · 2 min read
Human body questions are a reliable part of Everyday Science papers. They are short, factual and, once revised, quick to answer. This guide puts the most-asked facts into tables you can revise in a few minutes.
Organs and glands
| Fact | Answer |
|---|---|
| Largest organ | Skin |
| Largest internal organ and largest gland | Liver |
| Organ that produces insulin | Pancreas |
| Filtering unit of the kidney | Nephron |
| Air sacs where gas exchange happens | Alveoli |
| Chambers in the human heart | 4 (two atria, two ventricles) |
| Part of the eye that controls light entry | Iris |
Bones and teeth
| Fact | Answer |
|---|---|
| Bones in an adult | 206 |
| Longest bone | Femur (thigh bone) |
| Smallest bone | Stapes (in the ear) |
| Permanent teeth in an adult | 32 |
| Milk teeth in a child | 20 |
Blood
| Component | Job |
|---|---|
| Red blood cells | Carry oxygen (using haemoglobin) |
| White blood cells | Fight infection |
| Platelets | Help blood to clot |
- Universal red-cell donor: O negative
- Universal recipient: AB positive
Vitamins and deficiency diseases
| Deficiency | Disease or effect |
|---|---|
| Vitamin A | Night blindness |
| Vitamin B1 (thiamine) | Beriberi |
| Vitamin C | Scurvy (bleeding gums) |
| Vitamin D | Rickets (soft, weak bones) |
| Vitamin K | Poor blood clotting |
| Iodine | Goitre |
| Iron | Anaemia |
Memory tip: vitamin D is the “sunshine vitamin”, made in the skin in sunlight, and it is needed to absorb calcium for strong bones, which is why its deficiency causes rickets.
Common infections and their causes
| Disease | Cause | Spread by |
|---|---|---|
| Malaria | Plasmodium parasite | Female Anopheles mosquito |
| Dengue | Virus | Mainly Aedes mosquitoes |
| Tuberculosis | Bacterium (Mycobacterium tuberculosis) | Air, through coughing |
| Polio | Virus | Mainly contaminated food and water |
Common trap: malaria is not caused by a virus or bacterium; it is caused by a parasite.
Other useful numbers
- Normal body temperature: about 37 °C (98.6 °F)
- Chromosomes in a normal human body cell: 46 (23 pairs)
Revise in two minutes
Cover the right-hand column of each table and try to recall every answer. Mark the ones you miss, and revisit only those tomorrow. Then test yourself with our Human Body and Health MCQs. For more look-alike science facts, see 20 facts candidates commonly mix up.