Answer:
The correct answer will be- control samples.
Explanation:
A scientific experiment is performed to test the proposed hypothesis because on the basis of results the hypothesis could be proved and disproved.
The experimental design must contain two types of experimental samples: the samples on which the experiments are performed called "experimental samples" and the samples which act as a reference to the experimental samples called "control samples" as they lack the variable to be studied.
In the given question, the statements provide the clue that the experiment is performed on the experimental samples whereas the control sample on which the variable to be studied is missing.
Thus, control samples are the correct answer.