Búscalo, Wikipedia es bien!!!
The controlled experiments are performed by the scientists, when they want to study the changes in the sample on changing a single variable. So, the correct answer is option (b).
In case, all variables are kept same, no changes would be observed in the experiment sample. A controlled experiment can be performed on living thing as well as non living. But, controlled experiment cannot be performed on the things which are influenced by a lot of variables, as they cannot create realistic results. So, the option (a), (c), and (d) are incorrect.
Explanation:
Correct Answer: No change in serum glucocorticoid level
Response Feedback:Primary adrenal insufficiency would be indicated when the adrenal cortex fails to produce cortisol when synthetic ACTH is administered. Serum cortisol levelswould increase following ACTH administration if the adrenal cortex is functioning properly. Primary adrenal insufficiency occurs when there is no change in the serum glucocorticoid level.