Singapore N(T)-Level Science, The Human Body and Health: the digestive system, the respiratory system, the circulatory system, and diet, health and disease
An N(T)-Level Science module overview for The Human Body and Health (SEAB 5148). Trace how the digestive system breaks down food, how the respiratory system takes in oxygen, how the circulatory system transports oxygen and food, and how a balanced diet and healthy choices prevent disease, with links to every dot point.
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What this module is about
The Human Body and Health module of N(T)-Level Science (SEAB 5148) is about how the body takes in food and oxygen, moves them around, and stays healthy. As a Normal (Technical) module it keeps the focus on the everyday: what happens to a meal, why we breathe, how the heart pumps blood, and the choices that keep us well.
This overview ties the threads together and links to every dot point page in the module, each with its own worked answers and practice questions.
The digestive system
The module starts with the digestive system. Food is broken down so its useful parts can be absorbed. It is chewed in the mouth and mixed with saliva, passes down the gullet to the stomach where it is churned with digestive juices, and then enters the small intestine where digestion finishes and the broken-down food is absorbed into the blood. The large intestine absorbs water from what remains, and the waste leaves the body.
The respiratory system
Next comes the respiratory system. Air travels in through the nose or mouth, down the windpipe (trachea) and into the lungs, reaching tiny air sacs called alveoli. There, gas exchange happens: oxygen passes into the blood and carbon dioxide passes out to be breathed out. We need oxygen so that body cells can release energy from food by respiration. Breathing in and out moves air in and out of the lungs.
The circulatory system
The third dot point is the circulatory system. The heart is a muscular pump that pushes blood around the body. Blood travels in three kinds of vessel: arteries carry blood away from the heart, veins carry blood back to the heart, and capillaries are tiny vessels where substances pass to and from the cells. Blood carries oxygen and digested food to the cells and removes waste such as carbon dioxide.
Diet, health and disease
The module finishes with diet, health and disease. A balanced diet contains carbohydrates (energy), proteins (growth and repair), fats (stored energy), vitamins and minerals (keeping the body working), fibre (digestion) and water. Healthy choices, a balanced diet, regular exercise and good hygiene, help prevent disease, while too much fatty or sugary food can lead to problems such as obesity.
How this module is examined
- Trace food through the gut. Mouth, gullet, stomach, small intestine (absorption), large intestine (water).
- Explain gas exchange. Oxygen in, carbon dioxide out at the alveoli; oxygen is needed for respiration.
- Match blood vessels to their jobs. Arteries away from the heart, veins back, capillaries for exchange.
- Link diet to health. Name each food group's job and a healthy choice that prevents disease.
Check your knowledge
A mix of recall and application questions covering the module. Attempt them under timed conditions, then check against the solutions, and use the dot point pages for fuller practice.
- Name the part of the digestive system where digested food is absorbed into the blood. (1 mark)
- Name the tiny air sacs in the lungs where gas exchange happens. (1 mark)
- State why the body needs oxygen. (1 mark)
- State the job of an artery and the job of a vein. (2 marks)
- Name two things that blood carries to the body cells. (2 marks)
- Name the food group needed for growth and repair. (1 mark)
Sources & how we know this
- Singapore-Cambridge GCE N(T)-Level Science Syllabus 5148 — Singapore Examinations and Assessment Board (2026)