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: Seedless and seed are the two divisions of vascular plants.

Answer: What are the two divisions of vascular plants?

Question: A bow wake is created when the wave source moves faster than the wave propagation speed.

Answer: What is created when the wave source moves faster than the wave propagation speed?

Question: You call sound that has a wave frequency higher than the human ear can detect ultrasound.

Answer:
What do you call sound that has a wave frequency higher than the human ear can detect?