Which term best describes the quantities that can change in an experiment?

The term that best describes the quantities that can change in an experiment is "variables." In the context of scientific experiments, variables are the factors or conditions that can be manipulated or measured. This includes independent variables, which are intentionally changed to observe their effect, and dependent variables, which are observed and measured as a response to changes in the independent variable.

Variables are crucial for scientific inquiry because they allow researchers to establish relationships between different factors. By controlling or measuring these variables, scientists can draw conclusions and make predictions based on their observations.

In contrast, the other terms have specific meanings in scientific terminology that do not relate to changing quantities. "Species" refers to a group of organisms that can interbreed, "constants" are the factors that remain unchanged throughout the experiment to ensure that the test remains fair and results are valid, and "hypotheses" are proposed explanations for a phenomenon that can be tested through experimentation. These distinctions highlight why "variables" is the most appropriate term for quantities that can change during an experiment.