Hi! :)
Answer: Maria says that Bruno must not apologize for his sister's actions out loud. That could mean trouble for both Bruno and Maria. Any sense that Maria or Bruno disagrees with Nazi ideology could mean trouble.
The correct answer would be the bride groom. I am assuming that this is based on the poem by Joanna Baillie.
One species(the parasite) benefits while the other species (the host) is harmed
Where's the example that was given? I would love to help but didn't see an example.