Nokea
Which property of matter refers to the measure of the force of gravity acting on an object?
- A. Mass
- B. Weight
- C. Density
- D. Volume
Correct Answer: B
Rationale: The correct answer is 'Weight.' Weight is the measure of the force of gravity acting on an object. Mass refers to the amount of matter in an object, density is the mass per unit volume of a substance, and volume is the amount of space an object occupies. In this context, the question specifically asks for the property related to the force of gravity, making 'Weight' the correct choice. 'Mass' is the measure of the amount of matter in an object, 'Density' is the mass per unit volume of a substance, and 'Volume' is the space occupied by an object, none of which directly measure the force of gravity on an object.
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Which of the following is NOT a major component of a healthy blood pressure reading?
- A. Systolic pressure (peak pressure during ventricular contraction)
- B. Diastolic pressure (pressure within arteries during ventricular relaxation)
- C. Pulse pressure (difference between systolic and diastolic pressure)
- D. Blood oxygen saturation levels. While blood oxygen levels are crucial for overall health, they are not directly reflected in a blood pressure reading.
Correct Answer: D
Rationale: Blood oxygen saturation levels are essential for overall health but are not directly part of a blood pressure reading. A healthy blood pressure reading consists of systolic pressure, diastolic pressure, and pulse pressure. Systolic pressure represents the peak pressure during ventricular contraction, diastolic pressure reflects the pressure within arteries during ventricular relaxation, and pulse pressure is the difference between systolic and diastolic pressure. These components collectively provide information about the pressure variations within the arteries throughout the cardiac cycle phases, contributing to the assessment of cardiovascular health. Therefore, choice D, blood oxygen saturation levels, is not a major component of a healthy blood pressure reading and is the correct answer. Choices A, B, and C are major components of a healthy blood pressure reading and directly relate to the pressure variations within the arteries during different phases of the cardiac cycle.
What is the primary cause of acne vulgaris, commonly known as acne?
- A. Dry skin
- B. Clogged pores and excess oil production
- C. Bacterial infection alone
- D. Vitamin deficiency
Correct Answer: B
Rationale: The primary cause of acne vulgaris is clogged pores and excess oil production. Acne develops when hair follicles become clogged with oil and dead skin cells, creating an environment for bacteria to thrive, leading to inflammation and acne breakouts. While dry skin, bacterial infection alone, and vitamin deficiency can contribute to acne, they are not the main underlying cause. Therefore, the correct answer is clogged pores and excess oil production, as they form the basis for the development of acne vulgaris.
What does antidiuretic hormone (ADH) help the kidneys regulate?
- A. Acid-base balance
- B. Blood pressure
- C. Urine output by controlling water reabsorption
- D. All of the above
Correct Answer: C
Rationale: Antidiuretic hormone (ADH) helps the kidneys regulate urine output by controlling water reabsorption. ADH acts on the kidneys to increase the reabsorption of water, leading to a decrease in urine output. This helps the body conserve water and maintain proper fluid balance. ADH primarily affects urine output by controlling water reabsorption and does not directly regulate acid-base balance or blood pressure. Therefore, choices A and B are incorrect because ADH does not directly influence acid-base balance or blood pressure.
Which technology allows scientists to directly edit the human genome?
- A. Polymerase Chain Reaction (PCR)
- B. Gel electrophoresis
- C. DNA sequencing
- D. CRISPR-Cas9
Correct Answer: D
Rationale: CRISPR-Cas9 is the correct answer. A) Polymerase Chain Reaction (PCR) is used for amplifying specific DNA segments, not directly editing the human genome. B) Gel electrophoresis is for separating DNA fragments by size, not for genome editing. C) DNA sequencing determines DNA nucleotide order but does not directly edit the genome. D) CRISPR-Cas9 technology enables precise modifications in the DNA of organisms, including humans. It guides the Cas9 enzyme to specific genome locations for targeted edits, revolutionizing genetic research and offering various applications in gene editing and therapy. Unlike the other techniques mentioned, CRISPR-Cas9 is specifically designed to make changes in the genetic code itself, making it a powerful tool for genetic manipulation.
When is a solution considered saturated?
- A. More solute cannot be dissolved
- B. The solvent starts to evaporate
- C. The solution becomes cloudy
- D. It reaches a specific temperature
Correct Answer: A
Rationale: A solution is considered saturated when it has dissolved the maximum amount of solute that can be dissolved at a given temperature. At this point, adding more solute will not result in further dissolution, indicating that the solution is saturated. The other choices are incorrect because the solvent evaporating or the solution becoming cloudy are not definitive indicators of a saturated solution. Additionally, reaching a specific temperature does not determine saturation, as the solubility of a solute can vary with temperature. Therefore, the correct answer is that more solute cannot be dissolved in a saturated solution.