Answer and Explanation:
Your question wasn't really completed but i think the question was supposed to be like this :
"Of these events in “Top if the Food Chain,” which happens first?
A. Cats die from eating the bodies of infected geckos.
B. A species of wasp that eats caterpillars is killed off.
C. Villagers’ roofs collapse and are replaced with tin.
D. Cats are flown in from Australia to control the rat population."
And the answer for it is :
Option "B" A species of wasp that eats caterpillars is killed off.