Water that has large amounts of dissolved calcium and magnesium is referred to as hard water. Calcium and magnesium naturally occur in Earth materials such as limestone, magnesite, gypsum, and other minerals groundwater comes into contact with. Calcium is a vital component of bones and teeth. Calcium is also necessary for proper muscle action, blood clotting, and regulating the heartbeat. Magnesium is necessary for more than 300 biochemical processes in the body, such as regulating heartbeat and blood sugar levels, helping maintain normal blood pressure, and facilitating protein synthesis. The health benefits of drinking hard water have been well documented since the 1920s. One study investigated the effects of different amounts of dietary magnesium on rat survival rates. The first table shows the summary data from this study. Softening water has become a common practice in many homes. Soft water is water that has had the calcium and magnesium ions and other minerals removed to prevent the buildup of a residue called scale in pipes and appliances. Soft water also increases the effectiveness of soaps and detergents. Research around the health benefits of drinking hard water suggests that people may be at higher risk for certain diseases when their water lacks dissolved calcium and magnesium. The second table summarizes data from two human population studies that examined the role of dietary magnesium and cardiovascular health.
Which statement explains the central idea of the passage?
- A. People should consume as much magnesium as possible to ensure good cardiovascular health.
- B. People may experience health benefits from drinking hard water because it contains magnesium.
- C. People who live in rural environments are healthier than people who live in urban environments.
- D. People should stop the practice of softening water because it removes minerals that are necessary for good health.
Correct Answer & Rationale
Correct Answer: B
Option B accurately reflects the central idea by highlighting the potential health benefits of magnesium found in hard water. This aligns with the passage's focus on the relationship between magnesium intake and cardiovascular health. Option A is misleading as it suggests an excessive intake of magnesium is necessary, while the passage likely emphasizes balance rather than maximum consumption. Option C incorrectly generalizes health comparisons between rural and urban populations without specific evidence from the passage. Option D misrepresents the passage's message by implying a complete cessation of water softening, rather than discussing the importance of maintaining essential minerals like magnesium.
Option B accurately reflects the central idea by highlighting the potential health benefits of magnesium found in hard water. This aligns with the passage's focus on the relationship between magnesium intake and cardiovascular health. Option A is misleading as it suggests an excessive intake of magnesium is necessary, while the passage likely emphasizes balance rather than maximum consumption. Option C incorrectly generalizes health comparisons between rural and urban populations without specific evidence from the passage. Option D misrepresents the passage's message by implying a complete cessation of water softening, rather than discussing the importance of maintaining essential minerals like magnesium.
Other Related Questions
Which statement describes the motion of the object for the first 10 seconds?
- A. The object is moving at a constant speed.
- B. The object is doubling its speed every two seconds.
- C. The object is increasing its height.
- D. The object is accelerating.
Correct Answer & Rationale
Correct Answer: D
The motion of the object for the first 10 seconds indicates that it is accelerating, meaning its speed is increasing over time. Option A is incorrect because constant speed implies no change in velocity, which contradicts the evidence of acceleration. Option B suggests a specific pattern of doubling speed, which is not necessarily true without further information on the object's velocity changes. Option C, while it may imply upward motion, does not capture the essential aspect of acceleration, which is a change in speed rather than just height.
The motion of the object for the first 10 seconds indicates that it is accelerating, meaning its speed is increasing over time. Option A is incorrect because constant speed implies no change in velocity, which contradicts the evidence of acceleration. Option B suggests a specific pattern of doubling speed, which is not necessarily true without further information on the object's velocity changes. Option C, while it may imply upward motion, does not capture the essential aspect of acceleration, which is a change in speed rather than just height.
Based on the table, use the drop-down menus to make the following statement correct. _ experiences the least warming effect from CO2 because it has the _ of CO2 in its atmosphere.
- A. smallest amount
- B. largest amount
- C. Mars
- D. Planet L
Correct Answer & Rationale
Correct Answer: A,C
The statement highlights that Mars experiences the least warming effect from CO2 due to its atmospheric composition. Mars has a small amount of CO2 compared to other planets, which limits its greenhouse effect and consequently its warming. Option B, "largest amount," is incorrect as it contradicts the premise that a larger CO2 presence would lead to more warming. Option D, "Planet L," is not a recognized celestial body in this context and does not provide relevant information regarding CO2 levels. Thus, the combination of Mars with the smallest amount of CO2 accurately reflects the relationship between atmospheric composition and warming effects.
The statement highlights that Mars experiences the least warming effect from CO2 due to its atmospheric composition. Mars has a small amount of CO2 compared to other planets, which limits its greenhouse effect and consequently its warming. Option B, "largest amount," is incorrect as it contradicts the premise that a larger CO2 presence would lead to more warming. Option D, "Planet L," is not a recognized celestial body in this context and does not provide relevant information regarding CO2 levels. Thus, the combination of Mars with the smallest amount of CO2 accurately reflects the relationship between atmospheric composition and warming effects.
Which statement describes one feature of the Rutherford-Bohr atom model that the Thomson model does not share?
- A. The Rutherford-Bohr model identifies different elements by the numbers of particles present.
- B. The Rutherford-Bohr model maintains the observed neutral charge of atoms.
- C. The Rutherford-Bohr model correctly describes the types of particles in the atom.
- D. The Rutherford-Bohr model restricts the positive charge of the atom to the nucleus.
Correct Answer & Rationale
Correct Answer: D
The Rutherford-Bohr model uniquely restricts the atom's positive charge to the nucleus, a significant advancement over the Thomson model, which depicts a diffuse positive charge throughout the atom. Option A is incorrect as both models can identify elements based on particle numbers, but the Rutherford-Bohr model adds more detail about electron arrangements. Option B is misleading; both models account for atomic neutrality, but the Rutherford-Bohr model provides a clearer structure. Option C is also inaccurate; while the Rutherford-Bohr model describes particles more accurately, it does not fundamentally change the types of particles present compared to Thomson's model.
The Rutherford-Bohr model uniquely restricts the atom's positive charge to the nucleus, a significant advancement over the Thomson model, which depicts a diffuse positive charge throughout the atom. Option A is incorrect as both models can identify elements based on particle numbers, but the Rutherford-Bohr model adds more detail about electron arrangements. Option B is misleading; both models account for atomic neutrality, but the Rutherford-Bohr model provides a clearer structure. Option C is also inaccurate; while the Rutherford-Bohr model describes particles more accurately, it does not fundamentally change the types of particles present compared to Thomson's model.
The cladogram shows the relatedness of several organisms based on shared characteristics. Which characteristic separates catfish from frogs?
- A. Suborbital fenestra
- B. Amniotic egg
- C. Four limbs
- D. Bony skeleton
Correct Answer & Rationale
Correct Answer: B
The presence of an amniotic egg is a key characteristic that distinguishes frogs from catfish. Frogs, as amphibians, undergo a life cycle that includes an aquatic larval stage, while catfish, as fish, do not produce amniotic eggs and instead lay eggs in water. Option A, suborbital fenestra, relates to skull structure and is not a defining characteristic that separates these groups. Option C, four limbs, applies to frogs but not to catfish, which possess fins instead. Option D, bony skeleton, is present in both groups, making it an insufficient distinguishing trait.
The presence of an amniotic egg is a key characteristic that distinguishes frogs from catfish. Frogs, as amphibians, undergo a life cycle that includes an aquatic larval stage, while catfish, as fish, do not produce amniotic eggs and instead lay eggs in water. Option A, suborbital fenestra, relates to skull structure and is not a defining characteristic that separates these groups. Option C, four limbs, applies to frogs but not to catfish, which possess fins instead. Option D, bony skeleton, is present in both groups, making it an insufficient distinguishing trait.