Given a scientific passage and an answer, generate a question for the given answer.

[Q]: Passage: Wings of bats and birds serve the same function. Look closely at the bones inside the wings. The differences show they developed from different ancestors. Answer: bones inside wings
[A]: Wings of bats and birds serve the same function. which body part should you study to understand ancestral differences?

[Q]: Passage: Insects spread disease and destroy crops. However, they are essential for pollinating flowering plants. Answer: insects
[A]: What are essential for pollination, but can spread disease and destroy crops?

[Q]: Passage: Figure 9.3 Intervertebral Disc An intervertebral disc unites the bodies of adjacent vertebrae within the vertebral column. Each disc allows for limited movement between the vertebrae and thus functionally forms an amphiarthrosis type of joint. Intervertebral discs are made of fibrocartilage and thereby structurally form a symphysis type of cartilaginous joint. Answer: fibrocartilage
[A]:
What are intervertebral discs made of?