I think waves will be the same as the motion because their all going the same way if not im sorry and take the test again and pick b
Answer:
the question is a bit vague, but all machines exist to serve a purpose, or to do or accomplish a certain task.
Every program that interacts with people responds to a specific set of commands. The set of commands and the syntax for entering them is called the user interface and varies from one program to another. The DOS operating system makes a distinction between internal and external commands.
In the document...? Not sure what the question is.
