Which of the following statements is accurate?

a. useful energy out of a system is always more than the energy input of that system.

b. energy output of a system is always more than energy put into a system.

c. useful energy out of a system is always less than the energy input of that system.

it is a learned trait

explanation:

you must remain stopped until the stop signal is retracted and the red lights are turned off. approaching traffic in the opposite roadway of a divided highway shall not be required to stop, even if the school bus has the stop-arm extended and the alternately flashing warning signal lamps on.