Sound wave is a pressure caused by the vibration of something in a medium that transfers anergy, like air.
Answer:
Hugh Capet and his heirs they strengthened the monarchy in france [B] by establishing a dynasty that started as far as 987. the early days of France
Explanation:
Hugh Capet is known as the founder of the Capetian dynasty a Monarchy that ruled France from 987 to 1328. thereafter his heirs (cadet branches of the dynasty ) ruled the kingdom of France. All French kings since then have belonged to the dynasty through Louis Philippe
