Using controls in biological experiments is significant for ensuring the validity and reliability of results. Controls serve as a benchmark, allowing researchers to compare experimental results against a standard without the influence of the independent variable. By including control groups, scientists can isolate the effects of specific treatments, ensuring that observed changes are due to the manipulation of variables rather than external factors. This careful experimental design enhances the credibility of findings, enables reproducibility, and contributes to a better understanding of biological processes and phenomena.