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

Ultrasound, a diagnostic technology, uses high-frequency vibrations transmitted into any tissue in contact with the transducer.
What diagnostic technology uses high-frequency vibrations transmitted into any tissue in contact with the transducer?

Water plus other substances makes a(n) solution.
Water plus other substances makes what?

When waves of two different frequencies interfere, beating occurs.
When waves of two different frequencies interfere, what phenomenon occurs?