Marcie is driving Adam to the airport. Adam is telling Marcie about some financial difficulties he is having. Periodically, he asks Marcie for her opinion. According to the textbook, attending to the conversation may decrease activity in the areas of Marcie's brain critical for safe driving by nearly percent.

40%

Explanation:

Attention is a factor that helps a person in attending the stimulus from the environment. It is about the thought in the head. This is the ability of a person to pay attention to the important things and ignore rest those are much important. It helps human beings to survive and evolved themselves. Human beings are distracted by internal as well as external factors such as wandering thoughts in the mind and inviting ping on phone. It is the force that helps a person to focus on a particular task.  

Marcie while deriving was using her strength of concentrating on safe deriving which was around 40%

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