The starch remains in the dialysis bag because the molecules are bigger than the pores. The potassium-iodide enters the bag (this can be determined because the liquid inside the bag turns black or...
Depends, are you trying to decide what you want when you check out at the grocery store or what? If you want something to hold wet stuff like diapers or kitty litter, plastic works better every time....
Can't really say as it depends on brand and company of the makes, and what materials were used in the plastic(as not all plastic consists of the same things as plastic is a combination of many...