What happened to the average length of the potato cylinders (increased/decreased/remained the same) as the concentration of salt in the external solution increased

Decreased

Explanation:

As the concentration of salt in the external solution increased, the water potential of the external solution lowers.

The water potential of the cytoplasm inside potato cells becomes higher than that of the external solution.

There is a net movement of water molecules from the cytoplasms of potato cells to the external solution by osmosis, (because in osmosis, water molecules tend to move from a region of higher water potential to a region of lower water potential through a semi-permeable membrane- which is the potato cell membrane in this case)

As the potato cells lose so much water, the cells shrink hence the average length of potato cylinders decrease.

passing a magnet thought the

mixture , because iron gets attracted to magnet .