Final answer:
The scientific method is designed to decrease bias and increase validity, providing a structured and objective approach to scientific inquiry.
Step-by-step explanation:
The scientific method helps to decrease bias and increase validity. The correct answer is c. decrease, increase. The scientific method is a systematic process that involves making observations, formulating hypotheses, conducting experiments, and analyzing results to draw conclusions. By following this structured approach, scientists aim to minimize personal biases that might influence the outcome and to enhance the credibility and reproducibility of their findings, thus increasing validity. This method facilitates a more objective and accurate understanding of the natural world.