Nokea
Positive feedback mechanisms usually result in
- A. changes returning values away from a set point.
- B. stable conditions around a set point.
- C. unstable conditions.
- D. long-term changes.
Correct Answer: C
Rationale: Positive feedback mechanisms usually result in unstable conditions. In a positive feedback loop, the output enhances or amplifies the changes that are occurring, leading to a deviation from the initial set point. Therefore, positive feedback does not bring values back towards the set point (Choice A). Choice B is incorrect because positive feedback does not promote stability around a set point. Choice D is also incorrect as positive feedback mechanisms typically do not lead to long-term changes; instead, they intensify the initial change, causing instability.
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What is the membrane on the surface of a lung called?
- A. visceral pleura
- B. parietal pleura
- C. visceral pericardium
- D. parietal pericardium
Correct Answer: A
Rationale: The correct answer is A: visceral pleura. The membrane covering the surface of the lungs is called the visceral pleura. It is a serous membrane that is in direct contact with the lung tissue. Choices B, C, and D are incorrect because the parietal pleura covers the inner surface of the chest wall and diaphragm, the visceral pericardium covers the surface of the heart, and the parietal pericardium is the outer layer of the pericardium surrounding the heart, respectively.
Macromolecules are built of
- A. Monomers
- B. False
- C. Not Sure
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: Monomers. Macromolecules are built from smaller subunits called monomers. Monomers join together through chemical reactions to form larger molecules known as macromolecules. Option B is incorrect because it does not provide the accurate information regarding macromolecules. Option C is incorrect as it indicates uncertainty, which is not the case here. Option D is incorrect as there is a specific answer related to the composition of macromolecules.
The recent discovery of taste receptors that detect sweetness in the small intestine illustrates that
- A. chemical responses occur in various parts of the body.
- B. new discoveries about anatomy and physiology are still being made.
- C. everything about anatomy and physiology has been discovered.
- D. the molecular and cellular level is crucial in anatomy and physiology.
Correct Answer: B
Rationale: The recent discovery of taste receptors in the small intestine illustrates that new discoveries about anatomy and physiology are still being made. This finding demonstrates that our understanding of the human body is continuously evolving. Choice A is incorrect because the discovery does not imply that chemical responses occur in only one part of the body but rather showcases a specific new discovery. Choice C is incorrect as it is highly improbable that everything about anatomy and physiology has been discovered given the complexity of the human body. Choice D is incorrect as while the molecular and cellular level is important in anatomy and physiology, the primary focus of this discovery is on the new findings about the taste receptors in the small intestine.
What do positive feedback mechanisms do?
- A. Cause long-term changes.
- B. Move conditions away from the normal state.
- C. Bring conditions back to the normal state.
- D. Usually produce stable conditions.
Correct Answer: B
Rationale: Positive feedback mechanisms amplify or increase changes in a system, moving conditions away from the normal state. This makes choice B the correct answer. Choice A is incorrect as positive feedback does not cause long-term changes but rather accelerates deviations from the norm. Choice C is incorrect because positive feedback does not bring conditions back to normal; instead, it amplifies deviations. Choice D is incorrect as positive feedback does not usually lead to stable conditions but rather to further deviations from the normal state.
Living organisms use oxygen to __________________.
- A. reduce heat production
- B. accept electrons for cellular metabolism
- C. release energy stored in the molecules of food
- D. remove metabolic wastes
Correct Answer: C
Rationale: The correct answer is C. Living organisms use oxygen to release energy stored in the molecules of food through a process called cellular respiration. This process involves breaking down glucose molecules in the presence of oxygen to produce energy in the form of ATP. Choice A is incorrect because oxygen does not directly reduce heat production in organisms. Choice B is incorrect because oxygen is involved in accepting electrons rather than donating them in cellular metabolism. Choice D is incorrect because the removal of metabolic wastes is not the primary role of oxygen in living organisms.