Answer:
There are 195 countries in the world comprises of 193 countries that are member states of the United Nations and 2 countries that are non-member observer states
Sound wave is a pressure caused by the vibration of something in a medium that transfers anergy, like air.
The correct answer is - They formed long ago, and erosion has beveled them to their present elevation.
The Appalachian Mountain Range is one of the oldest mountain ranges on the planet. They have formed in the Ordovician Period, around 480 million years ago. When they formed and were at their peak, the Appalachians were much larger and higher than what they are in the present. The reason for their decline in size is attributed to the erosion. The erosion is a process that removes the material from its original position. This process has been influencing, at different rates, the Appalachians for almost half a billion years. Even though the erosion is not a process that acts very quickly, when put the time that it influenced these mountains we will see that it managed to lower them significantly. That process continues in the present, and in the manner in which the continents are moving, there shouldn't be any force that will help lift up the Appalachians again, but instead they will continue to shrink until they are flattened in the distant future.
Okay, so we're starting with d = rt. "Distance equals rate times time." If you divide both sides by t, you would get r = d/t. So, your answer is A. Another explanation: let's say you've traveled 120 miles in 2 hours. How fast were you going? To solve that, you would divide your distance (120) by your time (2) to get 60 mph. So, rate = distance/time.Hope this helps.
