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How does meiosis differ from mitosis?
- A. Meiosis is used for repairing the body. Mitosis is used for cell reproduction.
- B. Meiosis is used for sexual reproduction. Mitosis is used for asexual reproduction.
- C. Meiosis occurs in various organisms. Mitosis occurs in various organisms.
- D. Meiosis produces cells that are genetically different. Mitosis produces cells that are genetically identical.
Correct Answer: D
Rationale: Meiosis is the process of cell division that results in the formation of sex cells (gametes) with only half the number of chromosomes as the parent cell, leading to genetically different cells. In contrast, mitosis is a cell division process that produces two daughter cells that are genetically identical to each other and the parent cell, maintaining the same chromosome number. Therefore, the correct answer is D, as meiosis and mitosis differ in their genetic outcomes - meiosis results in genetic diversity, while mitosis maintains genetic identity. Choices A, B, and C are incorrect because they do not accurately distinguish between meiosis and mitosis. Meiosis is not used for repairing the body or asexual reproduction, and the occurrence of both processes in various organisms does not highlight their primary differences in genetic outcomes.
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In an oxidation reaction,
- A. an oxidizing agent gains electrons.
- B. an oxidizing agent loses electrons.
- C. a reducing agent gains electrons.
- D. a reducing agent loses electrons.
Correct Answer: B
Rationale: In an oxidation reaction, the substance being oxidized loses electrons, not gains them. An oxidizing agent is responsible for causing oxidation in another substance by accepting electrons, hence it undergoes reduction and loses electrons. Therefore, the correct statement is 'an oxidizing agent loses electrons,' making choice B the correct answer. Choices A, C, and D are incorrect because in an oxidation reaction, the oxidizing agent does not gain electrons, a reducing agent does not gain electrons, and a reducing agent does not lose electrons.
What is the process called in which a substance changes from a gas to a liquid?
- A. Condensation.
- B. Evaporation.
- C. Sublimation.
- D. Vaporization.
Correct Answer: A
Rationale: Condensation is indeed the correct answer. It is the process by which a substance changes from a gas to a liquid. This occurs when the temperature of a gas decreases enough for its particles to lose energy and come together to form a liquid. On the other hand, evaporation is the process of a liquid changing to a gas. Sublimation is the direct transition of a substance from a solid to a gas without passing through the liquid phase. Vaporization, on the other hand, is the general term for the process of a liquid changing to a gas, which includes both evaporation and boiling.
Which nervous system controls voluntary motor movement?
- A. Parasympathetic
- B. Sympathetic
- C. Autonomic
- D. Somatic
Correct Answer: D
Rationale: The correct answer is D: Somatic. The somatic nervous system is responsible for controlling voluntary motor movements. It includes the motor neurons that innervate skeletal muscles and allows us to consciously control our movements. The parasympathetic and sympathetic nervous systems are part of the autonomic nervous system, which controls involuntary functions such as heart rate and digestion. Therefore, choices A, B, and C are incorrect as they are components of the autonomic nervous system and are not primarily responsible for voluntary motor movements.
Which of the following describes an experiment?
- A. The final math grades for a group of students passing through each year of elementary school are examined.
- B. The health trends of smokers in a small random sample are examined.
- C. Citizens in a local community are surveyed to determine concerns related to the next election.
- D. The effects of a new drug are tested on a group of participants.
Correct Answer: D
Rationale: Option D describes an experiment because it involves testing the effects of a new drug on a group of participants. In an experiment, researchers intentionally manipulate an independent variable (in this case, the new drug) to observe its effects on a dependent variable (the participants' health outcomes). This method allows for establishing cause-and-effect relationships between variables, which is a key characteristic of experimental research design. Choices A, B, and C do not represent experiments. Choice A involves observational analysis of math grades, choice B involves observational analysis of health trends, and choice C involves a survey, none of which involve manipulating variables to establish cause-and-effect relationships.
What are the cellular functions of cilia and flagella?
- A. Cilia and flagella are responsible for cell movement.
- B. Cilia and flagella synthesize proteins.
- C. Cilia and flagella help protect the cell from its environment.
- D. Cilia and flagella have enzymes that help with digestion.
Correct Answer: A
Rationale: Cilia and flagella are microtubule-based structures found on the surface of many eukaryotic cells. Their primary function is to facilitate cell movement. Cilia are short, numerous, and move in coordinated waving motions to move substances along the cell's surface. Flagella are longer and usually limited to one or a few per cell, providing a propeller-like movement for the cell. Both cilia and flagella aid in cell motility and are essential for various cellular functions, primarily involved in cell movement rather than protein synthesis, protection, or digestion. Therefore, choice A is correct as it accurately describes the primary function of cilia and flagella. Choices B, C, and D are incorrect as cilia and flagella are not involved in protein synthesis, cell protection, or digestion in cells.