Life Processes decision map (NRTE)
Choose Nutrition, Respiration, Transportation or Excretion from the question.
Step 1 — Study the figure
Cover the label key on the image, name each numbered part, then check the explanations below.
Step 2 — Diagram details for students
What this diagram shows
NRTE is a decision map for Life Processes questions: Nutrition, Respiration, Transportation, Excretion. First decide which process the question is testing, then recall the matching organs and keywords. This prevents mixing digestion with excretion or breathing with respiration.
Numbered parts — mark & remember
Match each number on the figure with the meaning below. Say the function aloud once.
1 Nutrition
Nutrition means taking in food and converting it into a usable form for energy and body materials. Plants use photosynthesis (autotrophic); humans digest food along the gut (heterotrophic). Look for words like food, digestion, villi, or starch in questions.
2 Respiration
Respiration releases energy from food, mainly glucose, often as ATP. Breathing only moves air; respiration is the biochemical energy process. Keywords include pyruvate, mitochondria, aerobic, and anaerobic.
3 Transportation
Transportation moves materials to cells that need them. In humans this is blood, heart, vessels and lymph; in plants it is xylem and phloem. Keywords include circulation, translocation, and transpiration pull.
4 Excretion
Excretion removes metabolic wastes such as urea formed in the body. It is not the same as egestion of undigested faeces. In humans the nephron filters blood; plants may store or release wastes differently.
How to read this figure
- Ask: is the question about food, energy, moving materials, or wastes?
- Pick the NRTE box first, then write the detailed answer.
- Keep egestion out of excretion answers.
Redraw for board marks
- Draw four large boxes labelled N, R, T, E.
- Add one human and one plant example under each.
- Add arrows showing continuous maintenance of life.
Board answer tip: Start long answers by naming the life process (NRTE), then explain organs and mechanism.
Exam tips — don’t lose marks
- Egestion ≠ excretion — this is a favourite trap.
- Plants also show all four processes; give plant examples when asked.
- Respiration is not only “breathing in oxygen”.