Final answer:
The safeguards against bias in a clinical trial include designing the research plan before contacting Dr. Jones, utilizing randomization and blinding, and ensuring objective measurements.
Step-by-step explanation:
The safeguards against bias in a clinical trial include designing the research plan before contacting Dr. Jones, utilizing randomization and blinding, and ensuring objective measurements. Limiting Dr. Jones's contribution is not a safeguard against bias as it does not directly address the potential for bias in the study design or data collection. By designing the research plan in advance, using randomization and blinding, and ensuring objective measurements, researchers can minimize bias and produce reliable data.