In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.

Q: Question: What type of cell layer do flatworms have? Answer: mesoderm

A: Mesoderm type of cell layer do flatworms have.
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Q: Question: What type of animal in the sea spend most of their lives as medusae? Answer: jellyfish

A: Jellyfish type of animal in the sea spend most of their lives as medusae.
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Q: Question: What do scientist's believe mercury's core is mostly made of? Answer: melted iron

A:
Melted iron do scientist's believe mercury's core is mostly made of.
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