Problem: 
Q: You are presented with the quiz "What comes from eggs?"   But you don't know the answer, so you turn to your teacher to ask for hints. He says that "mollusks are invertebrates such as the common snail" and "all mollusks come from eggs".   So, what's the best answer to the question?
Answer: snails
Problem: 
Q: You are presented with the quiz "Desertification implies what?"   But you don't know the answer, so you turn to your teacher to ask for hints. He says that "erosion causes deposition" and "desertification implies soil erosion".   So, what's the best answer to the question?
Answer: soil deposition
Problem: 
Q: You are presented with the quiz "What converts chemical energy into sound?"   But you don't know the answer, so you turn to your teacher to ask for hints. He says that "afirecracker converts chemical energy into sound" and "fireworks are illegal, including firecrackers".   So, what's the best answer to the question?
Answer:
a firework