A payment to a more powerful ruler or country is a (blank)

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Ireally need this answer sombody fast fast

Waves are used in many practical applications to support work, entertainment, and health. one example is the use of ultrasound imaging to safely track the development of a growing fetus. what is a specific example of a practical application of waves in medicine, entertainment, safety, or other fields? provide a brief explanation of how the properties of waves are useful to that application.

Ineed the answer to question 1 , i’m desperate