In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

Q: Metals often crystallize in a _ dimensional version of the hexagonal closest packed structure.

A: three
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Q: Hoof balance is _ dimensional geometry.

A: four
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Q: Puppy teeth begin to erupt until all the baby teeth are in by about five to _ weeks of age.

A:
six
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