instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: tobacco smoke causes fatal lung disease in nonsmokers. Answer: tobacco smoke
answer:
What still causes fatal lung disease in nonsmokers?

question:
Passage: The jointed appendages of arthropods may be used as legs for walking. Being jointed makes them more flexible. Try walking or climbing stairs without bending your knees, and you'll see why joints are helpful. In most arthropods, the appendages on the head have been modified for other functions. Figure below shows some of the head appendages found in arthropods. Sensory organs such as eyes are also found on the head. Answer: walking
answer:
What may the jointed appendages of arthropods be used for?

question:
Passage: Immovable joints do not allow the bones to move at all. In these joints, the bones are fused together by very tough collagen. Examples of immovable joints include the joints between bones of the skull. You can see them in Figure below . Answer: immovable joints
answer:
The joints that are between the bones that make up the skull are what kind of joints?