Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Q: The active transport of ions across the membrane causes an electrical gradient to build up across the plasma membrane.

A: The active transport of ions across the membrane causes an electrical gradient to build up across the what?
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Q: The second step in eukaryotic cell division is division of nucleus part of the cell.

A: The second step in eukaryotic cell division is division of which part of the cell?
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Q: A theory is another name for a broad explanation that is supported by a great deal of evidence.

A:
What is another name for a broad explanation that is supported by a great deal of evidence?
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