Question 199·Medium·Rhetorical Synthesis
While researching marine biology, a student has compiled the following notes:
- Single-celled algae called dinoflagellates inhabit many coastal waters.
- When the water is disturbed, dinoflagellates emit quick flashes of blue light.
- The light results from an enzyme-driven reaction: luciferase acts on the molecule luciferin in the presence of oxygen.
- This chemical reaction converts stored chemical energy into visible light, a process known as bioluminescence.
- Nighttime beachgoers often see waves that appear to glow neon blue.
The student wants to explain how dinoflagellates produce light when the water is disturbed. Which choice most effectively uses relevant information from the notes to accomplish this goal?
For rhetorical synthesis questions, start by underlining the task words in the question (such as “how,” “why,” “to show a contrast,” or “to emphasize a problem”). Then skim the notes and group them into what is directly needed to fulfill that task versus what is just background or examples. Next, eliminate answer choices that (1) leave out the key type of information the task demands—here, the mechanism—and (2) add distracting details from the notes that do not serve the stated goal (like tourists or locations). Choose the option that uses the most relevant notes in a clear, focused sentence that directly accomplishes the stated purpose.
Hints
Focus on the key word in the question
Reread the prompt and underline what the student wants to do: explain how dinoflagellates produce light when the water is disturbed. You need a sentence that describes a process, not just a description of glowing waves.
Decide which notes matter most
Look at the bullet points and ask: which ones tell you what reaction happens inside the cells, and which ones only tell you where, when, or who sees the light?
Watch out for extra, off-purpose details
Be suspicious of answer choices that focus on tourists, nighttime beaches, or where the organisms live. Ask: does this choice actually explain the mechanism that makes the light, or only describe what it looks like?
Step-by-step Explanation
Clarify the task in the question
The prompt says the student wants to explain how dinoflagellates produce light when the water is disturbed. That means the answer must:
- Describe a process or mechanism, not just a description.
- Connect that mechanism specifically to disturbed or moving water.
Identify the most relevant notes
Look at the bullet points and decide which ones help explain how the light is produced.
Relevant for the mechanism:
- “When the water is disturbed, dinoflagellates emit quick flashes of blue light.” (connects light to disturbance)
- “The light results from an enzyme-driven reaction: luciferase acts on the molecule luciferin in the presence of oxygen.” (gives the reaction)
- “This chemical reaction converts stored chemical energy into visible light, a process known as bioluminescence.” (explains what the reaction does)
Less relevant for the mechanism:
- Where they live
- What tourists see at night
The correct answer must focus on the chemical reaction triggered by water movement.
Check each answer against the goal and notes
Now compare options to the task:
- Does the choice explain the process that produces light, or just describe observations/locations?
- Does it connect the light production to motion/disturbance of the water?
- Does it use the enzyme reaction information instead of unrelated details about tourists or beaches?
Eliminate any answer that mainly talks about what people see or where the organisms live without giving the reaction that causes the light.
Select the sentence that explains the process
Only choice B directly uses the notes about an enzyme-driven reaction and the conversion of chemical energy into light, while also connecting it to motion in the water:
B) When motion in the water triggers dinoflagellates, an enzyme called luciferase reacts with luciferin and oxygen, converting chemical energy into blue light.
This exactly explains how dinoflagellates produce light when the water is disturbed, so B is correct.