Answer:
1. Nothing can be left in the past.
Explanation:
Ray Bradbury's "A Sound of Thunder" is a science fiction story set in the year 2055. It revolves around the story of a man going back into the past to enjoy hunting dinosaurs but ended up disturbing the past.
In the story, the character Eckles had hired a travel agency, "Time Safari Inc." to take him back to the age of dinosaurs so that he can go on a hunting expedition. While there, they began shooting the dinosaurs but were asked to retrieve the bullets as they cannot leave anything behind. The tour guide, Travis explains, <em>"The bullets! The bullets can't be left behind. They don't belong in the Past; they might change anything."</em>
Thus, the correct answer is option 1.
