Biology

The correct answer is: To eliminate bias from both participants and researchers.

Explanation:

In a double-blind study, both the participants and the researchers do not know which group the participants are in (whether they are receiving the treatment or a placebo). This design helps eliminate bias that might occur if either the participants or researchers have knowledge of the treatment assignment.

Bias could influence participants' behaviors or the researchers' observations and interpretations of the results. By ensuring neither party knows who is receiving the treatment, the study reduces the risk of biased outcomes, making the results more reliable and valid.

Here’s a breakdown of the options:

A."To ensure that both the ...