Question 8·200 Super-Hard SAT Reading Questions·Expression of Ideas
While researching a topic, a student has taken the following notes:
- The Venus flytrap (Dionaea muscipula) is a carnivorous plant native to the coastal wetlands of North and South Carolina.
- Each trap closes only when two different sensory hairs are touched within about 20 seconds, preventing false alarms.
- The closing mechanism is driven by rapid changes in cell pressure, not by muscular tissue.
- The trap snaps shut in roughly 0.1 seconds, making it one of the fastest movements in the plant kingdom.
The student wants to add a sentence to a paragraph that explains how some plants can execute rapid movements through internal pressure changes. Which choice most effectively uses relevant information from the notes to accomplish this goal?
For rhetorical synthesis, underline the exact purpose statement in the question (here, explaining rapid movement via internal pressure changes). Then cross-check each option against the notes for (1) direct relevance to that purpose and (2) strict factual accuracy—eliminate choices that omit the key mechanism or subtly misuse a detail (like confusing the 20-second trigger window with the closing time).
Hints
Key phrase in the goal
The sentence must support a paragraph about rapid movements through internal pressure changes. Look for an option that explicitly mentions cell pressure (and stays faithful to the notes).
Audit every detail against the notes
In the best option, every claim (speed, trigger condition, mechanism, location) must be directly supported by the bullet points—watch for subtle misuses of the 20 seconds detail.
Prefer the option that combines mechanism + rapidity
If more than one choice mentions cell pressure, choose the one that also correctly states the 0.1-second snap and the two-hair requirement without changing what those numbers mean.
Step-by-step Explanation
Identify what the sentence must accomplish
The new sentence must help a paragraph explaining rapid plant movement caused by internal pressure changes. So it should (1) describe a rapid movement and (2) attribute that movement to changes in cell pressure (not muscles or another cause), using only the notes.
Match the notes to the goal
Key relevant notes are:
- The trap snaps shut in roughly 0.1 seconds (rapid movement).
- The mechanism is rapid changes in cell pressure, not muscular tissue (internal-pressure explanation).
- It closes only when two different sensory hairs are touched within about 20 seconds (accurate condition; prevents false alarms).
The best sentence should combine the mechanism (cell pressure) with the rapid speed, and it may accurately include the trigger condition.
Check each option for accuracy and relevance to pressure-driven motion
- Option 1 gives speed and the two-hair condition, but it never mentions cell pressure, so it doesn’t directly support the paragraph’s focus on pressure-driven movement.
- Option 3 mentions cell pressure and the two-hair condition, but it incorrectly treats 20 seconds as the time the trap takes to close; the notes say the trap closes in about 0.1 seconds, and 20 seconds refers to the trigger window.
- Option 4 mentions cell pressure and speed, but it wrongly says the trap closes whenever a sensory hair is touched; the notes require two different hairs.
Only one option is both on-purpose (pressure-driven rapid motion) and fully consistent with the notes.
Select the most effective, fully supported sentence
The only choice that accurately connects rapid movement to rapid changes in cell pressure while also correctly stating the 0.1-second closing time and the two-hair/20-second trigger condition is:
“The Venus flytrap from the coastal wetlands of North and South Carolina shows rapid plant movement: rapid changes in cell pressure snap its trap shut in about 0.1 seconds, but only after two different sensory hairs are touched within about 20 seconds.”