<span>The muscles that can flex, extend and abduct the arm, are the voluntary muscles, such as the biceps, triceps, and delts. These muscle play a crucial role in mobility of the arm.</span>
True! Earth is beginning to become very overcrowded and combined with the amount of people of the planet and the carelessness that they all have for it, the earth is slowly beginning to show it's age. Of course, no one will act on this opinion, because it is quite illegal to just kill people, but it is true!
They are called abrasion.
It's more like something losing its power
Response would be correct, as in response to environment.