Hi Schachfreizeit.
Strengthen and Weaken questions will always involve a conclusion because their correct answers always strengthen or weaken the support for a conclusion.
However, the conclusion is not always directly stated and it's not always in the passage.
Sometimes, the conclusion is implied.
For example: The directors have developed a plan for making sure that the employees can get their nutrition from plant-based foods.
That sentence implies that the directors have concluded that their plan will work.
In other cases, the conclusion is in the question stem.
For example: Which if the following, if true, would do the most to confirm that the cause of the outcome is the flapping of birds' wings?