Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: Skin grafts are required when the damage from trauma or infection cannot be closed with sutures or staples. Watch this video (http://openstaxcollege. org/l/skingraft) to learn more about skin grafting procedures. Answer: skin grafts
What are required when the damage from trauma or infection cannot be closed with sutures or staples?