Answer:
a. cause and effect
Step-by-step explanation:
Controlled experiments provide insight into cause and effect relationships by manipulating a particular factor and observing the resulting outcome. They allow researchers to establish a direct connection between a specific cause (the manipulated factor) and its effect (the observed outcome). By carefully controlling other variables and implementing randomization, experiments help isolate the influence of the manipulated factor on the outcome. This systematic approach enables researchers to infer causal relationships and determine the extent to which the manipulated factor contributes to the observed changes. Controlled experiments play a crucial role in scientific inquiry, allowing researchers to test hypotheses, validate theories, and make informed decisions based on empirical evidence.