Nursing Elites

1. Homologous structures are similar structures in different organisms that have a common evolutionary origin. An example is:

• A. Butterfly wings and bird wings (analogous structures with different origins)
• B. The arm of a human, the wing of a bat, and the flipper of a whale
• C. The eyes of an octopus and a human (convergent evolution with different origins)
• D. The stinger of a bee and the barb of a cactus (unrelated structures)

Correct answer: B

Rationale: Homologous structures are similar structures found in different organisms that share a common evolutionary origin. The arm of a human, the wing of a bat, and the flipper of a whale are all examples of homologous structures. Despite serving different functions, they share a common underlying structure due to their evolutionary relationship, evidencing a shared ancestry. These structures are modified over time to suit the specific needs of each species. Option A (Butterfly wings and bird wings) refers to analogous structures with different origins. Option C (The eyes of an octopus and a human) describes convergent evolution where traits evolve independently. Option D (The stinger of a bee and the barb of a cactus) are unrelated structures.

2. Which part of the nervous system is responsible for the “fight-or-flight” response?

• A. Somatic nervous system
• B. Parasympathetic nervous system
• C. Sympathetic nervous system
• D. Enteric nervous system

Correct answer: C

Rationale: The sympathetic nervous system is responsible for the 'fight-or-flight' response, triggering the body's automatic response to a perceived threat or danger. This system initiates physiological changes like increased heart rate, dilated pupils, and the release of adrenaline, preparing the body to confront or escape the threat. The somatic nervous system (Choice A) controls voluntary movements, the parasympathetic nervous system (Choice B) is responsible for the 'rest and digest' response to promote relaxation and digestion, and the enteric nervous system (Choice D) regulates the gastrointestinal system. Therefore, they are not associated with the 'fight-or-flight' response.

3. What happens to the speed of a sound wave when it travels from air to water?

• A. It increases because water is denser.
• B. It decreases because water is denser.
• C. It remains the same.
• D. Speed depends on the frequency, not the medium.

Correct answer: B

Rationale: When a sound wave travels from air to water, the speed of sound decreases because sound travels faster in denser mediums. Water, being denser than air, causes the speed of sound to slow down. Choice A is incorrect because sound travels faster in denser mediums, so the speed would not increase. Choice C is incorrect because the speed of sound changes when transitioning between different mediums. Choice D is incorrect because while frequency does affect sound, the medium it travels through also plays a significant role in determining the speed of sound.

4. What is the process by which muscles convert chemical energy (ATP) into mechanical energy (movement)?

• A. Photosynthesis
• B. Cellular respiration
• C. Muscle contraction
• D. The sliding filament theory

Correct answer: C

Rationale: Muscle contraction is the correct answer. It is the process by which muscles convert chemical energy (ATP) into mechanical energy (movement). During muscle contraction, the sliding filament theory explains how actin and myosin filaments slide past each other, causing muscle fibers to shorten and generate force. Photosynthesis (option A) is the process by which plants convert light energy into chemical energy. Cellular respiration (option B) is the process by which cells generate ATP from glucose and oxygen. The sliding filament theory (option D) is a detailed explanation of the molecular events that occur during muscle contraction but is not the overall process of converting energy into movement; it focuses on the mechanism within the process of muscle contraction.

5. Which element has the lowest electronegativity value?

• A. Oxygen
• B. Fluorine
• C. Helium
• D. Chlorine

Correct answer: C

Rationale: The correct answer is Helium (C). Electronegativity is the tendency of an atom to attract electrons towards itself in a bond. Helium, as a noble gas, has a very low electronegativity because its outer electron shell is already full and stable, resulting in minimal attraction for additional electrons. Oxygen (A), Fluorine (B), and Chlorine (D) are all non-noble gas elements that have higher electronegativity values compared to Helium due to their electron configurations and tendencies to attract electrons.

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