developing a hypothesis after collecting data in the investigation limiting the amount of background research before the investigation designing an investigation with repeated trials during the investigation obtaining other opinions concerning what should happen during the investigation
I gave my students this multiple choice question: Biologists conduct investigations to learn about living organisms. Which method helps reduce bias during an investigation?

Only one answer is correct among these 4 choices:
- developing a hypothesis after collecting data in the investigation
- limiting the amount of background research before the investigation
- designing an investigation with repeated trials during the investigation
- obtaining other opinions concerning what should happen during the investigation

Could you tell me which one is correct?

designing an investigation with repeated trials during the investigation