Use the Following to Answer Questions

question 9

Multiple Choice

Use the following to answer questions
Scenario II
A psychologist was interested in the effects of sleep deprivation on performance on a vigilance task.Forty college students served as participants and were placed in either the sleep-deprivation group or the control group by coin flip.Both groups spent the night before the study in a sleep laboratory,but only the control group was allowed to sleep.By the next morning,the sleep-deprived group had been awake for the last 24 hours.At this time,both groups were provided a nutritious breakfast and,shortly thereafter,testing began in sound-attenuating cubicles,each equipped with a computer.The vigilance task consisted of monitoring the computer screen.Participants were instructed that red dots represented allied spacecraft and green dots represented enemy spacecraft.Throughout the 2-hour-long task,red dots moved across the screen in irregular patterns.Occasionally and unpredictably,a green dot would quickly move across the screen in a haphazard pattern.When a green dot appeared,the task of the participant was to move a stylus over the green dot and press a button,"destroying" the enemy spacecraft.The psychologist measured the percentage of these enemy targets that were detected and destroyed.
The results of this fictitious experiment are shown in Figure 2.2.
Figure 2.2
-(Scenario II) The independent variable was:

• A)the length of the vigilance task.
• B)the percentage of enemy targets destroyed.
• C)the degree of vigilance.
• D)sleep status.

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Definitions:

Tunica Media

The middle layer of the walls of arteries and veins, composed mostly of smooth muscle and elastic fibers, playing a key role in regulating blood pressure and flow.

Valves

Structures in the heart and veins that maintain blood flow in a single direction, preventing backflow.

Pulmonary Capillaries

Pulmonary capillaries are the tiny blood vessels located in the lungs that surround the air sacs (alveoli), where the exchange of oxygen and carbon dioxide takes place between the bloodstream and the lungs.

Systemic Capillaries

The smallest blood vessels in the body's systemic circulation, where the exchange of water, oxygen, carbon dioxide, and many other nutrients and waste substances between blood and the tissues occurs.