Nokea
Which of the following is an example of stabilizing selection?
- A. Selection that favors extreme traits in a population
- B. Selection that removes individuals with extreme traits
- C. Selection that maintains the current average trait in a population
- D. Selection that favors one specific trait over all others
Correct Answer: C
Rationale: - Stabilizing selection is a type of natural selection that favors the intermediate variants in a population, while selecting against the extreme traits. This results in the maintenance of the current average trait in the population.
- Option A is incorrect because stabilizing selection does not favor extreme traits; instead, it favors the average trait.
- Option B is incorrect because stabilizing selection does not remove individuals with extreme traits; it acts against extreme traits by favoring the intermediate variants.
- Option D is incorrect because stabilizing selection does not favor one specific trait over all others; it favors the average trait by selecting against extreme traits.
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Which of the following is NOT a type of antibody?
- A. IgA
- B. IgM
- C. Interferon
- D. IgG
Correct Answer: C
Rationale: A) IgA: This is a type of antibody found in mucosal areas such as the gut, respiratory tract, and genitourinary tract. It plays a role in mucosal immunity. B) IgM: This is a type of antibody produced during the primary immune response and is the first antibody to be produced in response to an infection. C) Interferon: Interferons are signaling proteins produced by cells in response to viral infections. They play a role in the immune response by interfering with viral replication, but they are not antibodies. D) IgG: This is the most abundant type of antibody in the bloodstream and is involved in long-term immunity. Therefore, the correct answer is C) Interferon, as it is not a type of antibody.
Which element is used in fertilizers due to its role in plant cell division and growth?
- A. Potassium
- B. Phosphorus
- C. Calcium
- D. Magnesium
Correct Answer: B
Rationale: Phosphorus is the correct answer. It is used in fertilizers due to its essential role in plant cell division and growth. Phosphorus is a key component of nucleic acids, such as DNA and RNA, which are essential for cell division and growth in plants. Potassium (Choice A) is important for overall plant health and functions like enzyme activation, but it is not specifically known for its role in cell division and growth. Calcium (Choice C) is crucial for cell wall structure and stability but not primarily for cell division. Magnesium (Choice D) is essential for chlorophyll production and photosynthesis, but it is not directly linked to plant cell division and growth.
What is the function of the pericardium, the sac surrounding the heart?
- A. To generate electrical impulses for heart contraction
- B. To transport blood throughout the body
- C. To provide lubrication for heart movement
- D. To protect the heart and anchor it in place
Correct Answer: C
Rationale: The pericardium is a double-walled sac that surrounds the heart and contains a small amount of fluid to provide lubrication for the movement of the heart within the chest cavity. It helps reduce friction as the heart beats and moves. Choice A is incorrect because the generation of electrical impulses for heart contraction is primarily the function of the heart's specialized conduction system. Choice B is incorrect as the pericardium is not involved in the transportation of blood throughout the body. Choice D is also incorrect as while the pericardium does protect the heart, its primary function is to provide lubrication and reduce friction.
Which neurotransmitter is associated with mood regulation, sleep, and appetite?
- A. Acetylcholine
- B. Dopamine
- C. Serotonin
- D. GABA (Gamma-aminobutyric acid)
Correct Answer: C
Rationale: The correct answer is C: Serotonin. Serotonin is a neurotransmitter that plays a crucial role in mood regulation, sleep, and appetite. It helps regulate emotions, mood, and behavior. Imbalances in serotonin levels have been associated with conditions such as depression, anxiety, and eating disorders.
Choice A, Acetylcholine, is primarily involved in muscle control and memory functions. Choice B, Dopamine, is associated with reward, motivation, and motor control. Choice D, GABA (Gamma-aminobutyric acid), is an inhibitory neurotransmitter that helps reduce neuronal excitability and is not directly linked to mood regulation, sleep, or appetite.
Which element has the same number of protons and neutrons?
- A. Carbon (C)
- B. Oxygen (O)
- C. Lithium (Li)
- D. Helium (He)
Correct Answer: D
Rationale: The correct answer is Helium (He). Helium has an atomic number of 2, meaning it has 2 protons. It also has 2 neutrons, which gives it a total mass number of 4. Therefore, Helium is an example of an element with an equal number of protons and neutrons.
Choice A (Carbon) has 6 protons and usually has more neutrons than protons. Choice B (Oxygen) has 8 protons and 8 neutrons, so the numbers are not equal. Choice C (Lithium) has 3 protons and usually has more neutrons than protons, so it does not fit the criteria of having the same number of protons and neutrons.