Answer:
The stereotypes Amir has are - Polish men are tough steelworkers and that the women cook lots of cabbage. Amir never met someone Polish until this old woman whose garden plot borders his. Amir and the old woman speak quite often. He noticed somenting. When her hundreds of seedlings start to sprout she refuses to thin them so she takes out the weak ones and gives the strong ones a chance to grow. The old woman told Amir she cannot bear to do the thinning because it reminds her too closely of her concentration camp, where the prisoners were inspected each morning and divided into two lines - the healthy to live and the others to die. Amir realises how useless the stereotypes he heard about Poles are because she allowed him to see her rich culture and unique perspective that she comes from. He no longer saw her as a Pole but rather a living human being which is unique in her own right.