Final answer:
Potato slices feel most flaccid in a hypertonic solution because of osmosis that causes cells to lose water and shrink.
Step-by-step explanation:
The question is inquiring about the state of potato slices in different solutions and when they would feel the most flaccid. Potatoes that feel flaccid have likely been in a hypertonic solution, where the water concentration inside the potato cells is higher than the water concentration in the external solution. This results in water moving out of the potato cells into the solution, causing the cells to shrink and the potato slices to become flaccid or limp. This is an example of osmosis, where water moves through a semi-permeable membrane from an area of high water concentration to an area of lower water concentration. While the information provided indicates a different topic related to potato spindle tuber viroid (PSTV), it isn't directly relevant to the explanation of why potatoes feel flaccid in certain solutions.