7. The passage suggests that Smetacek regarded the death of the alga bloom described in lines 34–36 as vindication of his theory that iron fertilization can lead to carbon sequestration.

an indication of the potential dangers of “dead zones” such as those in the Gulf of Mexico.

evidence that there was insufficient oxygen in the Southern Ocean to support large blooms.

a disappointment because the diatoms were being removed from the food chain.

8. The passage suggests that iron fertilization could potentially help the whale population primarily by

increasing the concentration of oxygen in the ecosphere.
decreasing the concentration of carbon dioxide in the atmosphere.
supporting an important food source for the whales.
reducing the demand for hunting in areas where the whales are endangered.

9. The “route” mentioned in line 48 refers to

an experimental procedure.
an economic difficulty.
an idealistic approach.
a mode of persuasion.

10. The tone of the final paragraph is best described as

sanguine
awestruck
apprehensive
fatalistic

11. What is the purpose of this text?

Expository
Rhetorical
Narrative

12. What is the central idea of this text?