why does a potatoe change its shape in water-concentration 80% and not in 90% concentration??

Answer 1

Looks like you're from the Dan Quayle school of spelling.

In a 90% concentration, it is in an isotonic solution.
In 80% it is in a hypotonic solution so water flows into the cells.

Answer 2

90% is isotonic..therefore it maintains

It depends on how the potatoe changes it shape, hypertonic will make the cells shrink and hypotonic will make them swell. You be the judge!

Answer 3

Endo osmosis: Process in which of H2O move through the semipermeable membrane from low conc.to high conc.