is a technique often used in studies investigating sleep patterns. Researchers place electrodes at various locations on a person’s head in order to record brainwaves. a.electroencephalography (eeg) b. functional magnetic resonance imaging (fmri) c. magnetic resonance imaging (mri) d. positron emission tomography (pet)

a. electroencephalography (eeg)

Explanation:

Electroencephalography is a method used in monitoring electrical activities in the brain. Electrodes are usually placed at various location's on the patients head in order to record brain waves.

It is used to detect sleep disorders by investigating sleep patterns, it is also used to detect stroke, brain damage, brain tumor and some other brain related disorders.

Functional magnetic resonance imaging (fmri) is used to monitor brain activities by detecting changes that arise as a result of blood flow.

Magnetic resonance imaging (mri) is a technique that involves the use of medical imaging to form pictures of anatomical structures and processes in the body.

Positron emission tomography (pet) is a technique that helps to show the state of an organ organ or tissue function.

answer; researchers typically cannot control people's sexual behaviors as would be necessary in an experiment;

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