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What term describes the maximum displacement of particles from their rest position in a wave?
- A. Frequency
- B. Wavelength
- C. Amplitude
- D. Velocity
Correct Answer: C
Rationale: The term that describes the maximum displacement of particles from their rest position in a wave is called the amplitude. Amplitude is a measure of the strength or intensity of a wave and is represented by the height of the wave from the rest position to the crest (or trough) of the wave. Frequency (A) refers to the number of complete wavelengths that pass a point in a given time. Wavelength (B) is the distance between two consecutive crests (or troughs) of a wave. Velocity (D) is the speed of the wave, not the maximum displacement of particles from their rest position.
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The number of protons in an atom is determined by its:
- A. Atomic mass
- B. Electron configuration
- C. Chemical properties
- D. Atomic number
Correct Answer: D
Rationale: The number of protons in an atom is determined by its atomic number. The atomic number represents the number of protons in the nucleus of an atom, which also determines the element's identity. Therefore, the correct answer is (D) Atomic number. Choices (A) Atomic mass, (B) Electron configuration, and (C) Chemical properties are not directly related to the number of protons in an atom. Atomic mass is the total mass of protons, neutrons, and electrons in an atom. Electron configuration refers to the arrangement of electrons in an atom's energy levels, and chemical properties are determined by the arrangement of electrons in the outermost energy level.
What is the name for the change in enthalpy (heat) associated with a chemical reaction at constant pressure?
- A. Entropy
- B. Enthalpy
- C. Gibbs free energy
- D. Heat of reaction
Correct Answer: D
Rationale: The correct answer is D, Heat of reaction. The heat of reaction, also known as the enthalpy change, is the amount of heat absorbed or released during a chemical reaction at constant pressure. Entropy (A) is a measure of the disorder or randomness of a system and is not specifically related to heat changes in a chemical reaction. Enthalpy (B) is the total heat content of a system and not just the change associated with a reaction. Gibbs free energy (C) is a measure of the energy available to do work in a system at constant temperature and pressure, but it is not the specific term for the heat change in a chemical reaction.
What is the function of arrector pili muscles?
- A. To control sweat production
- B. To contract and cause goosebumps
- C. To produce sebum
- D. To sense touch
Correct Answer: B
Rationale: The correct function of arrector pili muscles is to contract and cause goosebumps. These small muscles are attached to hair follicles in mammals. When they contract, they cause the hair to stand on end, resulting in goosebumps. This physiological response is often triggered by cold temperatures or emotional states like fear, helping mammals conserve heat or appear larger in threatening situations. Choices A, C, and D are incorrect. Arrector pili muscles are not involved in controlling sweat production (Choice A), producing sebum (Choice C), or sensing touch (Choice D).
Which of the following colligative properties refers to the elevation of the boiling point of a solution?
- A. Freezing point depression
- B. Vapor pressure lowering
- C. Osmotic pressure
- D. Boiling point elevation
Correct Answer: D
Rationale: The correct answer is D, 'Boiling point elevation.' Boiling point elevation is a colligative property that describes the increase in the boiling point of a solvent when a non-volatile solute is added to it. This occurs because the presence of solute particles in the solvent lowers the vapor pressure of the solution, requiring a higher temperature to reach the same vapor pressure as the pure solvent. Choices A, B, and C are incorrect. Freezing point depression refers to the lowering of the freezing point of a solution, vapor pressure lowering is the reduction in vapor pressure due to the presence of solute particles, and osmotic pressure is the pressure required to prevent the flow of solvent molecules across a semipermeable membrane in osmosis.
Molecular clocks utilize the accumulation of mutations in DNA sequences to estimate the evolutionary divergence time between species. This method relies on the assumption that:
- A. The rate of mutation is constant across all genes and all species.
- B. Species with more morphological similarities diverged more recently.
- C. Mutations are always beneficial and contribute to increased fitness.
- D. The fossil record provides the most accurate estimates of evolutionary relationships.
Correct Answer: A
Rationale: A molecular clock is a method used to estimate the time of divergence between species by measuring the accumulation of mutations in DNA sequences. This method relies on the assumption that mutations occur at a relatively constant rate over time. If the rate of mutation were not constant, it would be challenging to accurately estimate the evolutionary divergence time between species. Therefore, option A is the most appropriate choice as it aligns with the fundamental principle underlying the molecular clock hypothesis.
Option B is incorrect because the assumption that species with more morphological similarities diverged more recently does not directly relate to the concept of molecular clocks and the accumulation of mutations in DNA sequences.
Option C is incorrect because mutations are not always beneficial and do not always contribute to increased fitness. Mutations can be neutral or deleterious as well, and their accumulation is what is used to estimate evolutionary di