All of the following tracts decussate EXCEPT:

Correct Answer: D

Rationale: Vestibulospinal tract . The corticospinal tract decussatin the medullary pyramids, with most fibers crossing to form the lateral corticospinal tract for contralateral voluntary movement. The corticonuclear tract also decussates, though partially, as fibers from the cortex to cranial nerve nuclei (e.g., 7, 12) cross to innervate contralateral lower facial musclor tongue, evident in facial palsy from stroke. The tectospinal tract decussatin the midbrain, originating from the superior colliculus to coordinate head movements toward stimuli (e.g., visual reflexes). However, the vestibulospinal tract donot decussate; it descends ipsilaterally from the vestibular nuclei in the brainstem to spinal motor neurons, facilitating posture and balance (e.g., antigravity muscles). This ipsilateral nature is critical, as unilateral vestibular lesions cause same-side extensor tone changes, unlike crossed tracts. Thus, D is the exception among these descending tracts, making it the correct answer.

Correct Answer: B

Rationale: It is initiated voluntarily , which is not true. The vomiting center is in the medulla oblongata (A is true), near the area postrema, coordinating the reflex via the nucleus tractus solitarius. Choice B is false; vomiting is an involuntary reflex, unlike swallowing, triggered by medullary signals (e.g., nausea from toxins), not cortical control. Choice C is true; it involvcranial nerve 8 (vestibular, motion sickness), 9 (glossopharyngeal, sensation), and 10 (vagus, motility), forming the reflex arc. Choice D is correct; vestibular input (e.g., dizziness via cranial nerve 8) stimulatvomiting, as in seasickness. Medullary lesions abolish vomiting, while cortical damage donot, confirming its involuntary nature. Thus, B is the untrue statement, making it the correct answer.

Correct Answer: C

Rationale: Obese people react differently to food cucompared to non-obese people . Research, like fMRI studies, shows obese individuals exhibit heightened brain respons(e.g., in reward centers like the striatum) to food cues, driving overeating. Choice A is false; exercise boosts metabolism and calorie burn, critical for weight control per guidelinlike CDCs. Choice B is incorrect; no universal obese personality exists traits vary widely, debunking stereotypes. Choice D is wrong; stress often increaseating in obese individuals (emotional eating), unlike some non-obese who may eat less. is false; obese people are more, not less, responsive to food visuals, per behavioral studies. C reflects external cue sensitivity, a key obesity factor, distinguishing it from metabolic or personality myths, making it the correct answer.

Correct Answer: B

Rationale: Ventromedial hypothalamus is the feeding center , which is false. The ventromedial hypothalamus (VMH) is the satiety center lesions cause overeating, not hunger stimulation (Anand & Brobeck, 1951). The lateral hypothalamus drivfeeding. Choice A is true; anxiety triggers overeating in overweight people via stress hormones. Choice C is correct; metabolic rate drops in deprivation to conserve energy, per starvation studies. Choice D is true; personality variwidely among overweight individuals, lacking a uniform type. is accurate; exercise burns calories, aiding weight loss, per clinical guidelines. Bs error revershypothalamic rolVMH damage causobesity, not feeding initiation making it the exception and correct answer.

Correct Answer: B

Rationale: Gender identity in humans is established at the age of 3 . Gender identity self-perception as male, female, or otherwise typically solidifiby age 3, per developmental psychology (e.g., Kohlberg). Choice A is false; gender role (social behaviors) differs from sexual orientation (attraction). Choice C is incorrect; stereotypstem from culture, not just hormones, though biology contributes. Choice D is wrong; gender is identity, not attraction (orientation). is false; societal attitudshape gender norms, as seen in cross-cultural studies. Bs truth is supported by milestonchildren express gender by 2-3, stable by 3-4 unlike the conflated or oversimplified claims of A, C, D, E, making it the correct answer.