Eight-year-old Daria was having some disturbances in her sleep, so her parents took her to a children’s hospital to undergo various tests. She recalls sleeping in the hospital room with a bunch of wires stuck to her scalp. What technique was used in Daria’s sleep study?A) functional magnetic resonance imaging (fMRI)B) MEG (magnetoenchephalography)C) electroencephalograph (EEG)D) PET scan (positron-emission tomography)E) CT scan (computer axial tomography)

C. Electroencephalography (EEG)

Explanation:

This is an electrophysioloical method of recoding the electrical activities in the brain. The process is non invasive and involves placing wires across different regions of the scalp. It measures the voltage fluctuations resulting from ionic current within the neurons of the brain. This helps to study the state of the brain and rule out disorders

C) electroencephalograph (EEG)

Explanation:

The bunch of wires stuck to her scalp was to measure the ionic  differences(Na +/K+) in axoplasm of  her brain neuron, which when  sum up  from million of  neurons at different  electrode location on her scalp  generated electrical field.When this passes through the brain tissues and eventually to the scalp  it can be detected and  measured as spikes of brain activity on the monitor. This techniques is called EEG, and it is used to monitor electrical activities of the brain.

it is used for diagnosis of epilepsy,seizure, nacolepsy-sleep disorders etc.

Its operation principle is that any alteration from the usual spikes of electrical activities of the brain must be due to an anomaly in the brain's function.

the answer is:

carbon dioxide