Dale is trying to buy a dr. pepper from a vending machine. when he pushes the button nothing happens. dale pushes the button multiple times over the course of the next thirty seconds before accepting that it does not work. later, dale still does not want to give up on his dr. pepper. he remembers that one time he held the button down for ten seconds, which resulted in him getting his drink. he decides to try this. this is an example of

this is an example of operant variability.

Explanation:

Operant variability means that results of an operation may vary so responses are sometimes easy to predict, at other times responding seems highly variable, unpredictable, or even random. The inability to predict is generally attributed to ignorance of controlling variables.

i believe

clean air is essential for health and survival

clean air provides nitrogen gas for plant respiration

clean air supplies oxygen that enables living organisms to breathe

hope this

i am brianly

sorry if this doesn't