Question 14 - Reading and Writing Practice Test for the SAT Exam

In the Great Barrier Reef, marine biologists observe an intriguing phenomenon: large groups of coral release their gametes simultaneously in a mass spawning event. This reproductive strategy ensures a higher chance of fertilization and survival of the next generation. The released gametes float to the surface and are dispersed by the ____, aiding in the widespread distribution of potential new coral colonies.

Which choice completes the passage so that it conforms to the conventions of Standard English?