Final answer:
An objective summary should focus on factual details such as the underwater robot's testing environment, the threat lionfish pose to coral reefs, and the non-lethal method of the robot's capture of the lionfish.
Step-by-step explanation:
An objective summary of "Underwater Robot Vacuums Up Lionfish" should include key factual information that provides a straightforward report without subjective comments about the lionfish's appearance. It should mention that the underwater robot was tested in conditions suitable for the lionfish, likely a saltwater pool. The summary should also note that the lionfish poses a threat to coral reefs, impacting biodiversity and ecosystem health. Finally, it is crucial to include the fact that the vacuum robot captures the lionfish without killing them, suggesting a humane approach to their removal.