Sleep is:

Correct Answer: B

Rationale: Reversible unconsciousness . Sleep is a reversible, unconscious state with reduced responsiveness, per sleep science definitions. Choice A is false; permanence defincoma, not sleep. Choice C is incorrect; reflexdecrease in sleep (e.g., REM atonia). Choice D is wrong; sleep isnt conscious. is false; muscle activity drops, especially in REM. Bs truth reversibility distinguishsleep from coma or death, as seen in daily cyclmakes itthe correct answer over the mischaracterizations of A, C, D, E.

Correct Answer: D

Rationale: A lumbar puncture (LP) is contraindicated when there is a risk of causing harm, such as brain herniation or introducing infection. Suspected mass lesions of the brain or spinal cord increase intracranial or intraspinal pressure, risking herniation if CSF is removed. Symptoms of impending cerebral herniation also contraindicate LP due to the danger of worsening pressure dynamics. Skin infection at the puncture site , however, is not an absolute contraindication; while it increasinfection risk, it can often be managed with alternative sitor sterilization, unlike the other conditions which pose immediate, severe risks. Thus, D is the exception and the correct answer, as it donot universally prohibit LP in the same critical way as A, B, or C.

Correct Answer: D

Rationale: Mobius syndrome is a congenital condition involving cranial nerve deficits, typically VI (abducens) and VII (facial), leading to bilateral facial weakness and abducens paralysis , impairing eye abduction. Hypoplasia or agenesis of brainstem nuclei underlithese deficits. Feeding difficultiare common due to facial weakness affecting sucking/swallowing. However, mental retardation is not a consistent feature; most individuals have normal intelligence unless complicated by other factors. Thus, D is the exception and correct answer, as Mobius syndrome primarily affects motor cranial nervrather than cognitive function, distinguishing it from conditions with broader neurologic impact.

Correct Answer: C

Rationale: CSF is primarily produced by the choroid plexus, with about 25% from extrachoroidal sourc, true. A child produc~20 mL/hr , and CSF flows from lateral ventriclvia the foramina of Monro to the third ventricle , both true. CSF is absorbed by arachnoid villi , also true. However, the total CSF volume in an infant is ~50-100 mL, not 150 mL , which is closer to adult levels. Thus, C is false and the correct answer, as it overestimatinfant CSF volume, misaligning with developmental physiology.

Correct Answer: B

Rationale: In simple febrile seizures, EEG is not routinely needed , spikduring drowsiness are common , and post-seizure EEGs may show slowing , all true. EEG helps classify epilepsy if present. However, an abnormal EEG donot reliably predict recurrence or epilepsy ; studishow it lacks specificity for prognosis in simple cases, making it the exception and correct answer. This reflects EEGs limited predictive value in febrile seizures, focusing its role on diagnosis rather than risk assessment.