Question

why thin peel of onion is placed in a watch glass containing water​

Answer 1

Answer:

because the onion peel contain thin epidermal tissues which get easily dehydrated

if this happen then the cells present in onion peel will die hence it will make it unsuitable for any biology experiment

Explanation:

the dehydrated cells will eventually die which will be nothing but a useless peice of waste

but to prevent that from dehydration we fut it in a water filled petridish so that cell dont die