Where is the inferior oblique muscle located?

Correct Answer: B

Rationale: The inferior oblique, an extraocular muscle, resides in the eye socket, originating near the orbit's front and inserting on the eyeball, elevating and abducting it. Abdominal muscles (e.g., obliques) flex the trunk. Anterior neck hosts muscles like sternocleidomastoid. Facial muscles (e.g., zygomaticus) move skin. The inferior oblique's orbital location and eye movement role distinguish it, essential for gaze, unlike trunk, neck, or facial functions.

Correct Answer: C

Rationale: Intestinal symptoms like diarrhea, vomiting, and abdominal pain stem from toxins disrupting gut function. Enterotoxins, produced by bacteria such as Escherichia coli or Staphylococcus aureus, target intestinal cells, increasing secretion or reducing absorption by altering ion channels or tight junctions, as seen in cholera. Cytotoxins cause broader cell damage, not specific to the gut. Neurotoxins affect nerves, not digestion directly. Leukocidins attack immune cells, not intestinal ones. Enterotoxins' specific action on gut epithelium, leading to fluid loss and characteristic symptoms, distinguishes them as the cause, critical for diagnosing gastrointestinal bacterial infections.

Correct Answer: A

Rationale: Cellular respiration encompasses the breakdown of glucose to produce ATP, involving glycolysis, the Krebs cycle, and the electron transport chain. Glycolysis includes anaerobic glucose splitting, yielding pyruvate, which feeds the Krebs cycle under aerobic conditions. The Krebs cycle generates electron carriers, fueling the electron transport chain for ATP synthesis. Anaerobic splitting is a subset when oxygen is absent. Cellular respiration's integration of these stages, converting food to energy, makes it the overarching process, central to cellular metabolism across organisms.

Correct Answer: C

Rationale: Most bacteria thrive at 37°C (98.6°F), mimicking human body temperature, ideal for pathogens like E. coli in lab cultures. An incubator maintains this stable warmth, promoting growth. A lighted window (22°C) varies and is cooler, a refrigerator (7°C) slows metabolism, and a freezer (-12°C) halts it. The incubator's optimal temperature, matching bacterial physiology, ensures rapid division and colony formation, making it the best choice for cultivating diverse species.

Correct Answer: C

Rationale: Tropomyosin moves off actin's myosin-binding sites when Ca²⁺ binds troponin, which shifts tropomyosin, allowing myosin to bind actin for contraction. Ca²⁺ and troponin don't move off they enable the shift. Troponin doesn't block sites or move myosin it's regulatory. Troponin moving tropomyosin reverses roles tropomyosin shifts due to troponin. Tropomyosin's displacement by troponin-Ca²⁺ distinguishes it, key to exposing sites, unlike static or reversed pairings, central to sliding filament theory.