A mechanism explains how something works. A recommendation tells a person what to do. SPM Science rewards the first and does not ask for the second.
This lesson is in the health-themed science sub-cluster. It pairs with medicine categories at textbook level.
How do I tell them apart?
Use one trigger question: could this sentence be checked by an experiment about how the body or substance works? If yes, it is a mechanism. If it tells someone what to do, it is a recommendation.
| Statement | Type |
|---|---|
| Sweat evaporating removes heat from the skin | Mechanism |
| Antibiotics act on bacteria | Mechanism |
| Take an antibiotic for your sore throat | Recommendation |
| Insulin helps cells take in glucose | Mechanism |
| Skip breakfast to lose weight | Recommendation |
| Pain relievers reduce the sensation of pain | Mechanism |
Worked example: rewriting an answer
Question: Explain why a person feels cooler when a fan blows across wet skin. (2 marks)
Weak answer. “You should use a fan when you are hot.”
That sentence is advice, and it earns no mark because it does not explain.
Rewrite. Moving air carries away water vapour, so the water on the skin evaporates faster. Evaporation takes heat from the skin, so the skin cools.
The rewrite has two linked statements, which fits two marks. Each statement is a cause-and-effect step.
The mistake that costs marks
The slip is ending a good mechanism with advice. The first half earns marks. The last sentence adds nothing and may suggest you misread the question.
| Answer part | Marks? |
|---|---|
| “Evaporation takes heat from the skin” | Yes |
| “So everyone should drink this product” | No, recommendation |
If you notice “should” or “you must” in a draft answer, check whether it comes from the question or from you.
Check yourself
Decide whether each sentence is a mechanism or a recommendation: (a) “Plants take in carbon dioxide during photosynthesis.” (b) “Students should buy this supplement before exams.”
Answer
(a) is a mechanism: it describes how a process works.
(b) is a recommendation: it tells people what to do, and the statement has no evidence behind it.
What to study next
Continue with explaining the limits of a model used in a textbook illustration. The claim evidence revision desk gives extra practice at matching statements to evidence.
For a teacher to rewrite answers with you, see online one-to-one Science tuition.