instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: Some people think that gravity moves food through the esophagus. If that were true, food would move through the esophagus only when you are sitting or standing upright. In fact, because of peristalsis, food can move through the esophagus no matter what position you are ineven upside down! Just don't try to swallow food when you are upside downyou could choke!. Answer: peristalsis
answer:
What process moves food through the esophagus no matter which position the body is in?

question:
Passage: Many species use their body shape and coloration to avoid being detected by predators. The tropical walking stick is an insect with the coloration and body shape of a twig which makes it very hard to see when stationary against a background of real twigs (Figure 45.20a). In another example, the chameleon can change its color to match its surroundings (Figure 45.20b). Both of these are examples of camouflage, or avoiding detection by blending in with the background. Answer: detection by predators
answer:
Many species use their body shape and coloration to avoid what?

question:
Passage: Valence electrons are the outer-shell electrons of an atom. Answer: valence electrons
answer:
What are the outer-shell electrons of an atom called?