Question 81·Hard·Rhetorical Synthesis
While researching a topic, a student has collected the following notes:
• Lake Baikal (Russia): volume 23,600 cubic kilometers; surface area 31,722 square kilometers; holds about 20% of the world’s unfrozen surface fresh water.
• Lake Superior (North America): volume 12,100 cubic kilometers; surface area 82,100 square kilometers; holds about 10% of the world’s unfrozen surface fresh water.
The student wants to highlight how Lake Baikal stores considerably more water than Lake Superior even though it covers a much smaller surface area. Which choice most effectively uses information from the notes to achieve this goal?
For rhetorical synthesis questions, start by underlining the goal in the prompt (here, “more water” + “smaller surface area”). Then scan the notes and quickly restate the needed comparison in your own words (for example: Baikal is less than half the area but almost twice the water). Finally, eliminate any choices that (1) ignore one of the key ideas, (2) focus on irrelevant statistics, or (3) express the relationship in a vague or awkward way; the best answer will explicitly and efficiently state the comparison that matches the goal.
Hints
Restate the goal
The question wants a sentence that emphasizes two ideas at once: Baikal has much more water and at the same time has a much smaller surface area than Superior. Which choices clearly mention both?
Use the numbers in the notes
Look at the volumes (23,600 vs. 12,100) and the surface areas (31,722 vs. 82,100). How could you summarize these numbers to show that Baikal is smaller in area but bigger in volume?
Watch out for partial answers
Some choices talk mainly about world percentages or only about volume or area. Does the choice you’re considering clearly show both the area difference and the water-volume difference between the two lakes?
Focus on contrast words
Look for transition words or phrases like “even though,” “less than half,” or “twice as much” that help highlight a strong contrast between the lakes’ size and water volume.
Step-by-step Explanation
Identify the writing goal
The question states that the student wants to highlight how Lake Baikal stores considerably more water than Lake Superior even though it covers a much smaller surface area.
So the right sentence must do two things:
- Show that Baikal has more water than Superior.
- Show that Baikal has a smaller surface area than Superior.
Any option that leaves out one of these ideas or makes them unclear should be eliminated.
Translate the notes into comparisons
From the notes:
-
Water volume
- Baikal: 23,600 cubic kilometers
- Superior: 12,100 cubic kilometers → Baikal has almost twice Superior’s volume.
-
Surface area
- Baikal: 31,722 square kilometers
- Superior: 82,100 square kilometers → Baikal’s surface area is less than half of Superior’s.
Keep these two key comparisons in mind: less than half the area but almost twice the water.
Match each choice to the goal
Now check which answer choice clearly states both comparisons:
- One choice talks only about how much water each lake holds and how much of the world’s fresh water that represents, but does not mention surface area at all. That cannot meet the goal.
- Another choice gives the surface areas and then says Superior contains nearly half the water volume of Baikal. That implies Baikal has more water, but it puts the focus on Superior and never directly says that Baikal stores much more water despite its smaller area, so the intended contrast is weak and awkward.
- A third choice just tells us the combined percentage of the world’s unfrozen surface fresh water and says nothing about which lake is bigger or holds more water.
- The remaining choice directly compares both surface area and volume, using phrases like “less than half” for area and “almost twice” for volume, which exactly matches the student’s goal.
The answer that does all of this is the best one.
Confirm the correct choice
The only option that clearly states that Baikal is much smaller in surface area but holds almost twice as much water is:
Even though Lake Baikal’s surface area (31,722 square kilometers) is less than half that of Lake Superior (82,100 square kilometers), Baikal contains almost twice as much water—23,600 versus 12,100 cubic kilometers.