The first one would be frequency. Here’s what I found to support that “The number of waves passing a fixed point in a certain amount of time is called the The word frequent means “often,” so frequency measures how often a wave occurs. Frequency is often measured by counting the number of crests or troughs that pass by a given point in one second”
The second one would be a medium “Mechanical waves require a medium in order to transport their energy from one location to another. “
