When you wait in line, sometimes there is less or more people. Sometimes, you wait longer than other days. If there are more people, the time will go up. If there are less people, the waiting time will go down. So, the wait is dependent on the number of people.
1a. It is because each x only has 1 y and it has an equation 1b. It is not a function because each x has more than 1 y. 1c. It is not a function because there can be no equation written for this graph.