Question

The following paragraphs are from an essay about a major discovery in marine biology.

[1]
In 1977, a team of oceanographers aboard the research submersible *Alvin* descended into the Pacific Ocean near the Galápagos Islands. They expected to find a barren, freezing desert at the ocean floor, where sunlight could not reach. Instead, they discovered a bustling ecosystem of giant tube worms, blind crabs, and vast fields of clams thriving in the pitch-black waters.

[2]
To sustain this vibrant community without sunlight, a process entirely different from photosynthesis had to be occurring. Geochemists quickly identified that specialized bacteria were oxidizing toxic hydrogen sulfide spewing from the hydrothermal vents, converting the chemical energy into organic matter. This ground-breaking discovery of chemosynthesis challenged the long-held biological dogma that all life ultimately relies on solar energy.

[3]
Prior to this expedition, marine biologists had assumed that the deep ocean depended solely on a sparse "rain" of organic debris drifting down from the sunlit surface. The discovery of hydrothermal vents completely upended this model, proving that planetary heat could also fuel complex life.

[4]
Consequently, these hydrothermal vent communities became a primary model for studying how life might arise on other worlds, such as Jupiter's icy moon Europa. Before scientists could speculate about extraterrestrial life, however, they had to understand how this ecosystem survived in such extreme conditions.

For the sake of the logic and cohesion of this essay, where is the most appropriate place to position Paragraph 2?