Why is the answer repeated trials to in order to increase the validity reliability of your experiament?

Repeated trials can be used to ensure the precision of your results. For example, let's say you are measuring a substance with a scale. You can measure the same amount multiple times to ensure your scale is working properly, and to verify the level of precision the scale is using.

Repeated trials can also be used to control for variables. For example, if you are performing a chemical reaction, you could repeat the experiment with varying levels of humidity in the air to see the effect it has on the reaction.

Repeated trials by multiple scientists can be used to verify the accuracy of the data reported by another scientist. When a scientist publishes the results of an experiment, other scientists can attempt to reproduce the experiment to verify its legitimacy.