Nokea
Homeostasis exists if concentrations of water, nutrients, and oxygen in the body and heat and pressure __________.
- A. decrease steadily
- B. remain within certain limited ranges
- C. increase when the body is stressed
- D. fluctuate greatly between very high and low values
Correct Answer: B
Rationale: Homeostasis is the body's ability to maintain stable internal conditions despite external changes. To achieve this balance, concentrations of essential substances must remain within specific ranges. Choice A is incorrect because decreasing concentrations would not maintain stability. Choice C is incorrect as increasing concentrations when the body is stressed would disrupt homeostasis. Choice D is incorrect as fluctuating greatly between high and low values would also not support the body's stability. Therefore, the correct answer is B, as it aligns with the concept of homeostasis by emphasizing the need for stability within certain limits.
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Ceroid pigments and lipofuscin accumulate with aging, impairing a cell's ability to withstand the damaging effects of oxygen free radicals.
- A. TRUE
- B. FALSE
- C. Not Sure
- D. None of the above
Correct Answer: A
Rationale: The statement provided in the question is true. Ceroid pigments and lipofuscin are products of cellular damage and aging. These substances accumulate within cells over time and can impair cellular functions, including the ability to withstand the damaging effects of oxygen free radicals. Choice B, 'False,' is incorrect because the accumulation of ceroid pigments and lipofuscin does indeed impair a cell's ability to deal with oxidative stress. Choices C and D are also incorrect as the statement is true.
Which of the following best describes a blood clot stimulating further clotting?
- A. a positive feedback mechanism.
- B. a negative feedback mechanism.
- C. a process turning itself off.
- D. nervous system communication
Correct Answer: A
Rationale: A blood clot stimulating further clotting is an example of a positive feedback mechanism. In positive feedback, the response enhances or amplifies the original stimulus, leading to an increase in the activity. In this case, the formation of a blood clot triggers more clotting activity, creating a cycle of increasing clot formation. Negative feedback mechanisms, on the other hand, work to maintain homeostasis by counteracting changes. Choices B, C, and D are incorrect as they do not accurately describe the situation of a blood clot stimulating further clotting.
The ability of an organism to sense and react to changes in its body illustrates
- A. circulation.
- B. respiration.
- C. responsiveness.
- D. absorption
Correct Answer: C.
Rationale: The correct answer is 'responsiveness.' Responsiveness refers to the ability of an organism to detect and respond to stimuli in its environment. In this context, it specifically relates to an organism's ability to sense and react to changes within its body. Choices A, B, and D are incorrect. Circulation refers to the movement of fluids within an organism, respiration is the process of exchanging gases, and absorption is the uptake of substances by cells or tissues.
The anatomical term that indicates a structure close to the surface is
- A. anterior
- B. proximal
- C. superficial
- D. superior
Correct Answer: C
Rationale: The correct answer is 'superficial.' In anatomy, the term 'superficial' refers to a structure that is close to the surface of the body. Choice A, 'anterior,' refers to the front of the body, not specifically to depth. Choice B, 'proximal,' refers to a structure that is closer to the point of attachment or trunk of the body. Choice D, 'superior,' indicates a structure that is above or higher in position.
Paired organs, such as the kidneys or lungs, are said to be
- A. bisexual.
- B. bilingual.
- C. bilateral.
- D. bivalent.
Correct Answer: C
Rationale: The correct answer is C: 'bilateral.' Paired organs like the kidneys or lungs are described as bilateral because they occur in pairs on both sides of the body. Option A 'bisexual' refers to having both male and female reproductive organs, which is not the correct term for paired organs. Option B 'bilingual' refers to being able to speak two languages, which is not related to the description of paired organs. Option D 'bivalent' means having two valences, which is also unrelated to the context of paired organs.