Final answer:
Anna starts crying when she has to put her plant in the box because she has developed an attachment to it. The plant symbolizes something meaningful to her, and having to put it away and potentially lose it can be emotionally distressing.
Step-by-step explanation:
In the book Because of Mr. Terupt, Anna starts crying when she has to put her plant in the box because she has developed an attachment to it. The plant symbolizes something meaningful to her, and having to put it away and potentially lose it can be emotionally distressing.