Q: You are presented with the quiz "Eating food that contains what can have a negative impact on humans?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "eating food that contains pesticides can have a negative impact on humans" and "pesticides are chemicals that kill pests". So, what's the best answer to the question?

Choose your answer from:
- vitamins;
- antioxidants;
- Abnormal cell growth;
- pest-killing chemicals;
- Something that causes allergies;
- harmful substances;
- minerals;
- a pathogens;
A:
pest-killing chemicals