Nokea
What is the correct way to represent 8,600,000,000,000 in scientific notation with two significant figures?
- A. 8.6 x 10^12
- B. 8.6 x 10^-12
- C. 8.6 x 10^11
- D. 8.60 x 10^12
Correct Answer: A
Rationale: The correct way to represent 8,600,000,000,000 in scientific notation with two significant figures is 8.6 x 10^12. Scientific notation involves expressing a number as a decimal (with one non-zero digit before the decimal point) multiplied by a power of 10. In this case, 8,600,000,000,000 is correctly written as 8.6 x 10^12 to maintain two significant figures and the appropriate magnitude. Choice B (8.6 x 10^-12) is incorrect as it represents a very small number due to the negative exponent. Choice C (8.6 x 10^11) is incorrect as it does not account for the magnitude of the original number. Choice D (8.60 x 10^12) is incorrect because it unnecessarily adds a zero after the decimal point, which is not warranted by the original number's precision.
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What is the final phase of mitosis?
- A. Prophase
- B. Telophase
- C. Anaphase
- D. Metaphase
Correct Answer: B
Rationale: Telophase is indeed the final phase of mitosis. During telophase, the chromosomes have reached opposite poles of the cell, the nuclear envelope is re-forming around the separated sister chromatids, and cytokinesis may also occur, leading to the division of the cell into two daughter cells. Choice A, Prophase, is incorrect as it is the initial phase of mitosis where chromatin condenses into chromosomes. Choice C, Anaphase, is incorrect as it is the phase where sister chromatids separate and move towards opposite poles. Choice D, Metaphase, is incorrect as it is the phase where chromosomes align at the cell's equator before separating.
How many neurons typically comprise a sensory pathway?
- A. 1
- B. 2
- C. 3
- D. 4
Correct Answer: C
Rationale: A sensory pathway generally consists of three neurons: a first-order neuron, a second-order neuron, and a third-order neuron. The first-order neuron carries sensory information from the periphery to the spinal cord or brainstem. The second-order neuron then transmits this information to the thalamus or cerebellum. Finally, the third-order neuron projects the sensory input to the cerebral cortex for processing and perception. Therefore, the correct answer is 3 (C). Choices A, B, and D are incorrect as they do not align with the typical structure of a sensory pathway involving three neurons.
Which of the following statements about the autonomic nervous system (ANS) is true?
- A. It controls involuntary functions
- B. It contains motor (efferent) neurons
- C. It contains sensory (afferent) neurons
- D. It contains both parasympathetic and sympathetic nerves
Correct Answer: D
Rationale: The correct answer is D because the autonomic nervous system (ANS) is responsible for controlling involuntary functions and contains both parasympathetic and sympathetic nerves. Choices A and B are incorrect as they do not fully capture the role of the ANS. While the ANS does control involuntary functions, this is a broader concept than just the reflex arc. While the ANS does contain motor (efferent) neurons, it also includes sensory (afferent) neurons, which are not specifically mentioned in the question. Therefore, choice C is not fully accurate. Choice D provides the most accurate and comprehensive description of the autonomic nervous system by highlighting its components, the parasympathetic and sympathetic nerves, which work together to regulate various bodily functions.
Which of the following terms refers to the process of breaking large molecules into smaller molecules to provide energy?
- A. Metabolism
- B. Bioenergetics
- C. Anabolism
- D. Catabolism
Correct Answer: D
Rationale: The correct answer is 'D: Catabolism.' Catabolism specifically involves breaking down large molecules into smaller ones to release energy. It is the opposite of anabolism, which is the process of building larger molecules from smaller ones. 'Metabolism' (choice A) is a broader term that encompasses all chemical processes in an organism, including anabolism and catabolism. 'Bioenergetics' (choice B) refers to the flow and transformation of energy in a biological system, not specifically the breakdown of molecules for energy.
Which of the following best defines the term amphoteric?
- A. A substance that conducts electricity due to ionization when dissolved in a solvent
- B. A substance that can act as an acid or a base depending on the properties of the solute
- C. A substance that, according to the Br¸nsted-Lowry Acid-Base Theory, is a proton-donor
- D. A substance that donates its proton and forms its conjugate base in a neutralization reaction
Correct Answer: B
Rationale: An amphoteric substance can act as both an acid or a base depending on the environment. It can donate a proton (act as an acid) or accept a proton (act as a base), showing versatility in its behavior. Choice A is incorrect as it describes an electrolyte rather than an amphoteric substance. Choice C is incorrect as it defines an acid based on the Br¸nsted-Lowry Acid-Base Theory. Choice D is incorrect as it specifically refers to a substance donating a proton in a neutralization reaction, not capturing the dual behavior of an amphoteric substance.