Top: plant 艹, bottom: right 右 (This hand ナ/ feeds the mouth 口.) For the mnemonic think to the character "hard 固": Things 囗 (like: herbs, vegetables, meat) with age 古 get hard 固 - Here however we have the opposite:
Mnemonic
The plant 艹 that is put by hand ナ into the mouth 口 is: young.
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