Scientists agree that our planet is getting warmer. But is there a human cause for global warming, or is it a natural fluctuation in a long-term cycle? Warming cycles throughout Earth's history have caused glacial melting, animal and plant habitat shifts, and earlier flowering seasons for trees. These climate changes often correlate with changes in Earth's orbit known as Milankovitch cycles. For example, Earth's angle of axial tilt varies over the course of 41,000 years from 22.1° to 24.5%. At greater angles, Earth's poles receive more direct solar radiation, or insolation.
Increased insolation results in higher mean temperatures. The Milankovitch theory proposes that cycles in climate arise from these cyclical changes in Earth's orbit. According to one viewpoint, the current warming of our planet is just evidence of a Milankovitch cycle. However, current climate changes are occurring at a faster rate than those in the To explain the different rates, many scientists point to human use of fossil fuels. Fossil fuels release carbon dioxide (CO,) when burned. CO, traps thermal radiation in Earth's atmosphere, a phenomenon known as the greenhouse effect. Recent increased levels of CO, correlate very strongly with increased mean temperatures. Furthermore, the rate of Increase in CO, levels is also rising.
For this reason, many scientists conclude that climate change is anthropogenic (caused by humans). Data that support Milankovitch cycles do not necessarily contradict this conclusion. Supporters of the anthropogenic climate change model only need to demonstrate that the current warming deviates from Milankovitch cycles and that human activities provide a better explanation, Both the anthropogenic climate change model and the Milankovitch theory are consistent with some of the observed climate changes. However, only one offers the best explanation for the current warming of Earth.
Scientists are Interested in whether certain greenhouse gases have helped cause I recent temperature increases. The graph presents data on carbon dioxide and methane gas levels in the atmosphere for the past several centuries. Human activities began producing large quantities of both gases in the 1700s. This graph, combined with information from--------------------, supports ----------------------.
- A. The Milankovitch climate change model
- B. paragraph 3
- C. The anthropogenic climate change model
- D. Paragraph 2
Correct Answer & Rationale
Correct Answer: B, C
The graph illustrates the correlation between rising greenhouse gas levels and temperature increases, supporting the anthropogenic climate change model, which attributes climate change to human activities. Options B and C effectively connect the visual data with the broader context of human influence on climate. Option A, referencing the Milankovitch model, is incorrect as this model focuses on natural Earth cycles, not human impact. Option D lacks specificity and does not directly relate to the evidence presented in the graph. Thus, B and C provide the most relevant support for understanding the relationship between greenhouse gas emissions and climate change.
The graph illustrates the correlation between rising greenhouse gas levels and temperature increases, supporting the anthropogenic climate change model, which attributes climate change to human activities. Options B and C effectively connect the visual data with the broader context of human influence on climate. Option A, referencing the Milankovitch model, is incorrect as this model focuses on natural Earth cycles, not human impact. Option D lacks specificity and does not directly relate to the evidence presented in the graph. Thus, B and C provide the most relevant support for understanding the relationship between greenhouse gas emissions and climate change.
Other Related Questions
Two people are standing at the edge of a high cliff. One person throws a rock horizontally off the cliff. Which uncontrolled part of this investigation can prevent the rocks from hitting the ground at the same time?
- A. gravity
- B. mass of the rocks
- C. air resistance
- D. strength of the person
Correct Answer & Rationale
Correct Answer: C
When a rock is thrown horizontally, it is influenced by both gravity and air resistance. Gravity acts equally on both rocks, ensuring they fall at the same rate. The mass of the rocks does not affect the time it takes to hit the ground in a vacuum, as all objects fall at the same rate regardless of mass. The strength of the person throwing the rock only affects the initial horizontal velocity, not the fall time. However, air resistance can vary based on the shape and size of the rocks, potentially causing differences in descent time. Thus, air resistance is the uncontrolled factor that can prevent the rocks from hitting the ground simultaneously.
When a rock is thrown horizontally, it is influenced by both gravity and air resistance. Gravity acts equally on both rocks, ensuring they fall at the same rate. The mass of the rocks does not affect the time it takes to hit the ground in a vacuum, as all objects fall at the same rate regardless of mass. The strength of the person throwing the rock only affects the initial horizontal velocity, not the fall time. However, air resistance can vary based on the shape and size of the rocks, potentially causing differences in descent time. Thus, air resistance is the uncontrolled factor that can prevent the rocks from hitting the ground simultaneously.
which sentence describes a difference between artificial selection and natural selection?
- A. In natural selection, variation is heritable; in artificial selection, variation is not heritable.
- B. In natural selection, there is differential reproduction; in artificial selection, there is not differential reproduction.
- C. In natural selection, there is variation within the population of organisms; in artificial selection, there is no variation within the population or organisms.
- D. In natural selection, reproductive success is driven by naturally occurring processes; in artificial selection, reproductive success is driven by human-imposed processes.
Correct Answer & Rationale
Correct Answer: D
Natural selection occurs through naturally occurring processes where organisms with advantageous traits are more likely to survive and reproduce, leading to evolutionary change over time. In contrast, artificial selection involves human intervention, where specific traits are chosen for breeding based on human preferences. Option A is incorrect; both types of selection involve heritable variation. Option B misrepresents artificial selection, which also involves differential reproduction based on selected traits. Option C is inaccurate as artificial selection can still involve variation within the chosen traits. Thus, option D accurately highlights the fundamental distinction between the two processes.
Natural selection occurs through naturally occurring processes where organisms with advantageous traits are more likely to survive and reproduce, leading to evolutionary change over time. In contrast, artificial selection involves human intervention, where specific traits are chosen for breeding based on human preferences. Option A is incorrect; both types of selection involve heritable variation. Option B misrepresents artificial selection, which also involves differential reproduction based on selected traits. Option C is inaccurate as artificial selection can still involve variation within the chosen traits. Thus, option D accurately highlights the fundamental distinction between the two processes.
Which hypothesis is suitable for this investigation?
- A. Body temperature, breathing rate, and heart rate depend on the health of the subject.
- B. Many of the body's systems respond to exercise.
- C. Body temperature, breathing rate, and heart rate increase with exercise.
- D. Subjects at rest have better health than subjects that exercise.
Correct Answer & Rationale
Correct Answer: C
Option C effectively addresses the investigation by predicting a specific relationship: that body temperature, breathing rate, and heart rate will increase with exercise. This hypothesis is testable and directly relates to physiological responses during physical activity. Option A is too broad, as it suggests a general relationship between health and various physiological metrics without focusing on exercise. Option B, while relevant, lacks specificity regarding the measurable changes in body temperature, breathing rate, and heart rate. Option D presents a misleading comparison, as it contradicts established knowledge about the benefits of exercise for health.
Option C effectively addresses the investigation by predicting a specific relationship: that body temperature, breathing rate, and heart rate will increase with exercise. This hypothesis is testable and directly relates to physiological responses during physical activity. Option A is too broad, as it suggests a general relationship between health and various physiological metrics without focusing on exercise. Option B, while relevant, lacks specificity regarding the measurable changes in body temperature, breathing rate, and heart rate. Option D presents a misleading comparison, as it contradicts established knowledge about the benefits of exercise for health.
A diagram of a PV cell being exposed to sunlight is shown below. Click on the labels you want to select and drag them into the boxes to show the components of the PV cell.
- A. Phosphorus-injected layer
- B. Boron-injected layer
- C. Electric field
- D. Energy
Correct Answer & Rationale
Correct Answer: A,B,C
The components of a photovoltaic (PV) cell include the phosphorus-injected layer, which serves as the n-type semiconductor, and the boron-injected layer, acting as the p-type semiconductor. Together, these layers create a junction that facilitates the movement of electrons when exposed to sunlight. The electric field between these layers is crucial for separating charge carriers, enabling electricity generation. Option D, "Energy," is not a structural component of the PV cell but rather a result of its operation. It does not represent a physical part of the cell, making it an incorrect choice.
The components of a photovoltaic (PV) cell include the phosphorus-injected layer, which serves as the n-type semiconductor, and the boron-injected layer, acting as the p-type semiconductor. Together, these layers create a junction that facilitates the movement of electrons when exposed to sunlight. The electric field between these layers is crucial for separating charge carriers, enabling electricity generation. Option D, "Energy," is not a structural component of the PV cell but rather a result of its operation. It does not represent a physical part of the cell, making it an incorrect choice.