Answer:
I think the answer is y-z>0
Sound waves are most effective when traveling through solids. Less effective when in liquids and least effective in air.
Synthesis. Which is "<span>Noun. (plural syntheses) The formation of something complex or coherent by combining simpler things. (chemistry) The reaction of elements or compounds to form more complex compounds.".....According to www.dictionary.com.</span>
A way to explain it is that back then all the continents were together but soon after drifted apart the were in the same place sort of put they drifted apart so that's sorta what happened. Hope that helps a little