Question

identifying good scientific design
which best describes an experiment that had good scientific design?
most of the methods were different for each trial within the experiment.
the data could not be replicated in another experiment.
each trial was repeated several times during the experiment.

Explanation:

In a good scientific design, repeating trials helps reduce error and increase reliability. Different methods per trial (first option) would introduce variability and make results unreliable. Data that can't be replicated (second option) lacks validity. Repeating trials (third option) is a key aspect of good scientific design.

Answer:

Each trial was repeated several times during the experiment.