Phytoplankton play a crucial role in the ocean's uptake of carbon from the atmosphere. When alive, these tiny marine organisms...
GMAT Expression of Ideas : (Expression) Questions
Phytoplankton play a crucial role in the ocean's uptake of carbon from the atmosphere. When alive, these tiny marine organisms absorb atmospheric carbon via photosynthesis. ______ after they die, the phytoplankton sink to the seafloor, where the carbon in their cells gets stored in sediment, preventing it from cycling back into the atmosphere.
Which choice completes the text with the most logical transition?
Step 1: Decode and Map the Passage
Part A: Create Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'Phytoplankton play a crucial role in the ocean's uptake of carbon from the atmosphere.' |
|
| 'When alive, these tiny marine organisms absorb atmospheric carbon via photosynthesis.' |
|
| '[MISSING TRANSITION]' |
|
| 'after they die, the phytoplankton sink to the seafloor, where the carbon in their cells gets stored in sediment, preventing it from cycling back into the atmosphere.' |
|
Part B: Provide Passage Architecture & Core Elements
Main Point: Phytoplankton contribute to ocean carbon uptake both while alive and after death through different mechanisms.
Argument Flow: The passage establishes phytoplankton as important for carbon uptake, explains their living function (photosynthesis), then describes their post-death function (carbon storage in sediment).
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- Looking at our analysis, the sentence before the blank describes what phytoplankton do when alive (absorb carbon), and the sentence after describes what happens after they die (sink and store carbon)
- We need a transition that shows this is a temporal sequence - first one thing happens, then another
- The relationship is not contrast since both processes help with carbon management, and it is not elaboration since we are moving to a different time period and process
- So the right answer should signal a temporal progression from the living state to the post-death state
- This transition signals elaboration or providing more specific detail
- But we are not elaborating on photosynthesis - we are moving to a completely different time period and process (after death)
- This signals opposition between two ideas
- But both the living and post-death processes serve the same overall function (carbon management)
- There is no contradiction here
- This signals contradiction or opposition despite expectations
- But nothing in the passage suggests the post-death carbon storage is unexpected or contradictory
- This signals temporal sequence, which perfectly matches our analysis
- Shows the natural progression from what happens when alive to what happens after death
- Creates the logical flow: first they absorb carbon while living, then after death they sink and store it