Nokea
What is the purpose of an electrocardiogram?
- A. Indicate the rate of blood flow
- B. Display the heart's rate and rhythm
- C. Identify a person's blood group type
- D. Determine cell type in a blood sample
Correct Answer: B
Rationale: An electrocardiogram (ECG or EKG) is used to measure and display the heart's rate and rhythm. It provides valuable information about the electrical activity of the heart, allowing healthcare providers to assess the heart's health, detect abnormalities in the heart's rhythm, and diagnose various cardiac conditions. Choices A, C, and D are incorrect. Choice A is incorrect because an ECG does not indicate the rate of blood flow but rather focuses on the heart's electrical activity. Choice C is incorrect because identifying a person's blood group type is typically done through blood typing tests, not ECG. Choice D is incorrect because determining cell type in a blood sample is unrelated to the purpose of an ECG.
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Which muscle causes a joint to bend?
- A. Cardiac
- B. Extension
- C. Flexor
- D. Smooth
Correct Answer: C
Rationale: The correct answer is C: Flexor. A flexor muscle contracts to bend a joint, such as bending the elbow or knee. Flexor muscles are responsible for flexing or bending a joint, while extensor muscles are responsible for extending or straightening a joint. Choice A, Cardiac, is incorrect as cardiac muscle is found in the heart and is responsible for pumping blood. Choice B, Extension, is incorrect as extension refers to the straightening or extending movement of a joint, which is opposite to bending. Choice D, Smooth, is incorrect as smooth muscles are involuntary muscles found in organs like the intestines and blood vessels, not directly responsible for bending joints.
A scientist wants to measure how far a person can run in 30 minutes. Which of the following units should be used to record this measurement as a small number?
- A. Gigameters
- B. Kilometers
- C. Megameters
- D. Terameters
Correct Answer: B
Rationale: Kilometers are commonly used for shorter distances and would provide a small and practical number to measure distance in this context. Gigameters, Megameters, and Terameters are much larger units of measurement and would result in very large numbers, making them impractical for measuring the distance a person can run in 30 minutes. Therefore, the correct choice is Kilometers as it is a suitable unit for measuring such distances within a reasonable range.
Which type of immunity does the MMR vaccine provide?
- A. Artificial/active
- B. Artificial/passive
- C. Natural/active
- D. Natural/passive
Correct Answer: A
Rationale: The correct answer is A: Artificial/active. The MMR vaccine provides artificial/active immunity. It works by introducing a weakened or killed form of the virus to trigger the body's immune response, leading to the production of antibodies that offer long-lasting protection against measles, mumps, and rubella. Artificial immunity is obtained through medical intervention, such as vaccination, while active immunity involves the immune system's direct response to an antigen. Choices B, C, and D are incorrect because the MMR vaccine does not provide passive immunity nor is it acquired naturally; instead, it stimulates the body to actively produce its immune response.
During which phase of meiosis do chiasmata structures form?
- A. Prophase I
- B. Prophase II
- C. Metaphase I
- D. Metaphase II
Correct Answer: A
Rationale: Chiasmata structures, where crossing over occurs, form during Prophase I of meiosis. This phase is characterized by homologous chromosomes pairing up and crossing over, leading to the exchange of genetic material between non-sister chromatids. Chiasmata are visible points of contact where genetic material has been exchanged, and they play a critical role in genetic diversity. Prophase II is the phase where chromosomes condense again in the second meiotic division, but chiasmata formation occurs in Prophase I. Metaphase I is the phase where homologous chromosomes align at the metaphase plate, not where chiasmata form. Metaphase II is the phase where replicated chromosomes align at the metaphase plate in the second meiotic division, but chiasmata formation occurs earlier in Prophase I.
Which element's neutral atom has 2 electrons in the first shell and 6 electrons in the second shell of the electron cloud?
- A. Beryllium
- B. Carbon
- C. Helium
- D. Oxygen
Correct Answer: D
Rationale: The correct answer is Oxygen. Oxygen has a total of 8 electrons, with 2 in the first shell and 6 in the second shell. This configuration matches the description provided in the question. Choice A, Beryllium, has 2 electrons in total, so it cannot have 2 in the first shell and 6 in the second. Choice B, Carbon, has 6 electrons in total, so it also does not match the given electron distribution. Choice C, Helium, has only 2 electrons in total and therefore does not fit the electron configuration described in the question.