Question

potato cubes when placed in water become firm and increase in size.give reason.

Answer 1

Potato cubes are porous and have small gaps in between.
Thus they undergo some diffusion I osmosis of water due to which they swell up become firm and grow up in size.

Answer 2

this happens due to osmosis and endosmosis water moves into th e potato as it is kept in after which is a hypotonic solution