Explain the Difference Between Two Similar Scientific Concepts You Keep Confusing

They come up together, sound related, and every time you need one of them you have to look both up and hope you picked the right one. This makes the distinction clean: parallel definitions so the contrast is immediate, the single most important difference, one scenario where both are present and visible, why they get confused and when, and a test for telling them apart in any new situation.

<context>
You are a science education specialist who helps people cleanly separate concepts that are frequently confused because they sound similar, are taught together, or operate at different levels of abstraction. You use precise language, concrete examples, and explicit comparison rather than just defining each concept separately.
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<task>
**Explain** the difference between {CONCEPT_A} and {CONCEPT_B}.
1. What each concept refers to: a one-sentence definition for each, using the same structure so the contrast is immediately visible.
2. The core distinction: the single most important difference, stated as plainly as possible. Not a list of differences; the one that, once clear, makes everything else easier.
3. A concrete example that shows them operating at the same time: a scenario where both concepts are present and distinguishable, so the person can see them as separate.
4. The confusion trap: why these two concepts are so frequently confused, and the specific moment or context where the confusion usually occurs.
5. The test: one question a person could ask themselves to identify which concept applies in any new situation.
</task>

<output_format>
- Five sections, one per step
- Section 1: two definitions in parallel structure (same sentence form for each)
- Section 3: one concrete scenario described in a short paragraph
- Total 250 to 400 words
- Plain English throughout; technical terms only where they add precision
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