Final answer:
Miss. Crocker accuses Mama of "biting the hand that feeds" for being ungrateful to the white school board by covering racist content in the textbooks.
Step-by-step explanation:
In the book Roll of Thunder, Hear My Cry, when Miss. Crocker suggests that Mama is "biting the hand that feeds" her, she is implying that Mama is acting ungratefully or disrespectfully towards the white school board that provides the textbooks, despite the fact that these books are old and racist.
Miss. Crocker believes that Mama should be grateful for any books at all, even if they are damaged and contain derogatory content. Mama's subsequent actions of pasting over the offensive material in the textbooks signify her defiance against the system that seeks to oppress her community by providing substandard educational materials.