Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: Hydras and sea anemones are examples of apolyp.

Answer: Hydras and sea anemones are examples of what form?

Question: Although they differ vastly in hardness, pencil lead and diamonds both contain carbon.

Answer: Although they differ vastly in hardness, pencil lead and diamonds both contain what element?

Question: When amino acids bind together, they form a long chain called a(n) polypeptide, which is an essential component of protein.

Answer:
When amino acids bind together, they form a long chain called what, which is an essential component of protein?