Jennifer has oversight responsibility for the servicing and repair of her company's fleet of cars, so she frequently calls the garage mechanic to inquire whether service on various cars has been completed. because service completion times are unpredictable, she is likely to be reinforced with positive responses to her inquiries on a schedule.

variable-interval

Explanation:

In a variable-interval schedule, reinforcement is presented if the body emits at least one response after a variable interval of time. Generally, this scheme is represented by putting the average time of the variable interval. For example: VI-10min means that the booster is displayed after an average of 10 minutes and only for the first response issued.

The variable-interval schedule results in a high frequency of responses.

As Jennifer's company car repair and maintenance service completion times are unpredictable, it will likely be reinforced with positive answers to your questions. This is an example of variable-interval schedule.

    racial conflict and discrimination has existed ever since man learned to kill with rocks and bones. these conflicts arose from disputes between territory, power, wealth, religion, or simple difference. some of the most infamous racial disputes include slavery, the holocaust, and the civil rights movement.

    these listed disputes often resulted in casualties from all sides. riots, wars, imprisonment, and lynching are all commonly associated with racial conflict on severe levels.

      however, racism is an improving issue in recent decades. people are being more accepting and welcoming of diverse populations. though, the world isn't perfect and it will take much more time, if ever, until the world is rid of racism.

explanation:

with the profits from the european sales, merchants purchased europe's manufactured  goods, including tools and weapons. then the merchants shipped those manufactured  goods, along with the  american  sugar and rum, to west africa where they were bartered for  slaves.