Final answer:
The known bighead carp control sample acts as a positive control in an experiment, ensuring the test methods work and that any detected presence of bighead carp is accurate.
Step-by-step explanation:
The purpose of using a control sample that is known to be from bighead carp is d) . It acts as a positive control for the experiment. A control sample serves as a standard or reference against which the results of an experiment can be compared. In this case, having a known sample of bighead carp DNA allows scientists to confirm that their methods are capable of correctly identifying this species. This is crucial for experiments aimed at detecting the presence or absence of bighead carp in a particular area to manage and study invasive species and protect ecological community structures. The control sample supports the scientific method by providing a baseline that ensures the experimental set-up is functioning as intended and that the variable being tested is indeed responsible for the observed outcome.