Chromotography - Chromatogram

[soccerboi]

Why do peaks become broader with increased retention time?

[Phantom-II]

question from the heinemann book?
with low retention times, the substance is less adsorbed on the stationary phase, so it spends more time on the mobile phase
substances with higher retention times are more easily adsorbed, so it spends more time becoming adsorbed then desorbed, moving in and out of the stationary phase, which gives a greater possible range of retention times with each molecule, ie in paper chromatography the dot gets stretched wider.