Nokea
What is an alteration in the normal gene sequence called?
- A. DNA mutation
- B. Gene migration
- C. Polygenic inheritance
- D. Incomplete dominance
Correct Answer: A
Rationale: A DNA mutation is the correct term used to describe an alteration in the normal gene sequence. It refers to changes in the DNA sequence that can result in different traits or characteristics. Gene migration involves the movement of genes between populations, polygenic inheritance refers to the inheritance of traits controlled by multiple genes, and incomplete dominance is a pattern of inheritance where neither allele is dominant.
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When testing how quickly a rat dies based on the amount of poison it eats, which of the following is the independent variable and which is the dependent variable?
- A. How quickly the rat dies is the independent variable; the amount of poison is the dependent variable.
- B. The amount of poison is the independent variable; how quickly the rat dies is the dependent variable.
- C. Whether the rat eats the poison is the independent variable; how quickly the rat dies is the dependent variable.
- D. The cage the rat is kept in is the independent variable; the amount of poison is the dependent variable.
Correct Answer: B
Rationale: The correct answer is B. In this experiment, the independent variable is the amount of poison because it is what is being manipulated by the researcher. The dependent variable is how quickly the rat dies, as it is the outcome that is being measured based on the different amounts of poison administered. Choice A is incorrect because the independent variable should be what is being manipulated or changed, which is the amount of poison in this case. Choice C is incorrect because whether the rat eats the poison is not being varied or controlled by the researcher. Choice D is incorrect because the cage the rat is kept in is not relevant to the relationship being studied between the amount of poison and the rat's survival time.
How do organisms maintain homeostasis?
- A. By increasing their body temperature, blood pH, and fluid balance.
- B. By undergoing biochemical processes and absorbing energy to increase entropy.
- C. By undergoing biochemical processes to maintain the order of their external environment.
- D. By using free energy and matter via biochemical processes to work against entropy.
Correct Answer: D
Rationale: Organisms maintain homeostasis by utilizing free energy and matter through biochemical processes to counteract entropy, which helps in preserving internal stability. This process involves maintaining a balance within the organism's internal environment despite external changes, ensuring proper functioning and survival. Choice A is incorrect because increasing body temperature, blood pH, and fluid balance alone do not define the comprehensive process of maintaining homeostasis. Choice B is incorrect as absorbing energy to increase entropy goes against the concept of maintaining internal stability. Choice C is incorrect as maintaining the order of the external environment does not directly contribute to the organism's internal stability and balance.
Which of the following is the body cavity that contains the urinary bladder, urethra, and ureters?
- A. The thoracic cavity
- B. The pelvic cavity
- C. The abdominal cavity
- D. The spinal cavity
Correct Answer: B
Rationale: The correct answer is B, the pelvic cavity. The pelvic cavity houses organs related to the urinary and reproductive systems. The urinary bladder, urethra, and ureters are located in the pelvic cavity, making it the correct choice. The thoracic cavity contains the heart and lungs, while the abdominal cavity houses organs like the stomach and intestines. The spinal cavity, on the other hand, protects the spinal cord. Therefore, options A, C, and D are incorrect as they do not house the specific organs mentioned in the question.
Which of the following touch receptors respond to light touch and slower vibrations?
- A. Merkel's discs
- B. Pacinian corpuscles
- C. Meissner's corpuscles
- D. Ruffini endings
Correct Answer: A
Rationale: The correct answer is A, Merkel's discs. Merkel's discs are touch receptors that respond to light touch and slower vibrations, making them ideal for detecting subtle tactile stimuli. Pacinian corpuscles are specialized in detecting deep pressure and high-frequency vibrations, not light touch or slower vibrations. Meissner's corpuscles, on the other hand, are sensitive to light touch and low-frequency vibrations, but they do not specifically respond to slower vibrations. Ruffini endings are responsible for detecting skin stretch and continuous touch pressure, differentiating them from Merkel's discs, which are specifically attuned to light touch and slower vibrations.
Which of the following correctly lists the four properties that all types of muscle tissue share?
- A. Contractile, excitable, elastic, extensible
- B. Contractile, voluntary, elastic, extensible
- C. Contractile, excitable, voluntary, extensible
- D. Contractile, excitable, elastic, voluntary
Correct Answer: A
Rationale: The correct answer is A: 'Contractile, excitable, elastic, extensible.' All types of muscle tissue share these four properties. Muscle tissue can contract, respond to stimuli, stretch and return to its original shape (elastic), and extend or stretch (extensible). Choice B is incorrect because not all muscle tissues are voluntary (some are involuntary). Choice C is incorrect because not all muscle tissues are voluntary. Choice D is incorrect because not all muscle tissues are voluntary and lack the elastic property.