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

Answer: 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?

Question: Passage: The body of a cnidarian consists of two cell layers, ectoderm and endoderm. The cells surround a digestive cavity called the coelenteron (see Figure below ). Cnidarians have a simple digestive system. The single opening is surrounded by tentacles, which are used to capture prey. The tentacles are covered with nematocyst cells. Digestion takes place in the coelenteron. Nutrients are absorbed and gases exchanged through the cells lining this cavity. Fluid in the coelenteron creates a hydrostatic skeleton. Answer: tentacles

Answer: Cnidarians have a simple digestive system with a single opening surrounded by what type of structures, which are used to capture prey?

Question: Passage: Natural gas is often found along with coal or oil in underground deposits. This is because natural gas forms with these other fossil fuels. One difference between natural gas and oil is that natural gas forms at higher temperatures. Answer: coal and oil

Answer:
Natural gas is often found along with what other fossil fuels in underground deposits?