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

[Q]: Passage: The Prokaryotic Cell Recall that prokaryotes (Figure 22.10) are unicellular organisms that lack organelles or other internal membrane-bound structures. Therefore, they do not have a nucleus but instead generally have a single chromosomea piece of circular, double-stranded DNA located in an area of the cell called the nucleoid. Most prokaryotes have a cell wall outside the plasma membrane. Answer: nucleoid
[A]: Prokaryotic cells do not have a nucleus but instead generally have a single chromosome, a piece of double-stranded dna located in an area of the cell called the what?

[Q]: Passage: Frogs and toads are adapted for jumping. Salamanders and newts may walk or swim. Caecilians live in the water or soil and are the only amphibians without legs. Answer: caecilians
[A]: What is the only amphibian without legs?

[Q]: Passage: Pulmonary circulation is the part of the circulatory system that carries blood between the heart and lungs (the term "pulmonary" means "of the lungs"). It is illustrated in Figure below . Deoxygenated blood leaves the right ventricle through pulmonary arteries, which transport it to the lungs. In the lungs, the blood gives up carbon dioxide and picks up oxygen. The oxygenated blood then returns to the left atrium of the heart through pulmonary veins. Answer: carbon dioxide
[A]:
What gas do the lungs give up as they take in oxygen?