Question 12·Hard·Rhetorical Synthesis
While preparing to write a report, a student compiled the following notes:
- Biologists Elizabeth Blackburn and Carol Greider conducted pioneering research on chromosome ends (telomeres).
- Blackburn hypothesized that progressive telomere shortening could limit a cell’s capacity to divide, influencing aging.
- Greider, then a graduate student in Blackburn’s lab, isolated the enzyme telomerase in single-celled organisms (Tetrahymena), showing how cells rebuild telomeres.
- Greider’s experiments furnished direct evidence that telomerase actively lengthens telomeres.
- Blackburn and Greider later shared a Nobel Prize for their telomere research.
The student’s assignment is to explain how the two scientists’ contributions complemented each other. Which choice most effectively uses relevant information from the notes to fulfill this purpose?
For rhetorical synthesis questions, underline the task (here, explain how their contributions complemented each other). Then label each person’s role from the notes (e.g., hypothesis vs. experimental discovery/evidence). Choose the option that accurately links those roles into a single relationship, and eliminate options that merely list facts or add conclusions stronger than what the notes state.
Hints
Aim for a relationship, not a list
The correct option must show how one scientist’s work supports or extends the other’s—not just mention two separate facts.
Identify hypothesis vs. experimental evidence
One note is a hypothesis (an idea about what telomere shortening might do). Another note is experimental evidence (isolating telomerase and showing it lengthens telomeres). Look for an option that pairs those roles correctly.
Watch for overstatements and swapped roles
Eliminate choices that claim more than the notes support (like turning a hypothesis into a proven cause) or that add conclusions the notes never make.
Step-by-step Explanation
Restate the goal
The sentence must show how Blackburn’s and Greider’s work complemented each other—meaning one scientist’s contribution should build on, support, or help explain the other’s, not just list unrelated facts.
Extract the key contributions from the notes
From the notes:
- Blackburn: hypothesized that progressive telomere shortening could limit a cell’s ability to divide (with implications for aging).
- Greider: isolated telomerase in Tetrahymena and provided direct evidence that telomerase actively lengthens/rebuilds telomeres.
Choose the option that links the contributions accurately
The correct choice should connect Blackburn’s hypothesis (shortening may limit division) with Greider’s experimental discovery/evidence (telomerase rebuilds/lengthens telomeres), showing how Greider’s work helps explain a mechanism related to Blackburn’s idea. The option that does this most effectively is:
Blackburn proposed that telomere shortening limits cell division, and Greider isolated telomerase, showing how cells rebuild telomeres—a mechanism that helps explain Blackburn’s idea.