The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.

Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.

The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.

Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.

The Big Bang Theory states:

Scientists have long debated the origin of organic molecules on Earth. Organic molecules are those based on the atom carbon, which can form four distinct bonds in contrast to the fewer number allowed in most other non-metals. As a result of this property, carbon can give rise to the enormously complex molecular shapes necessary for life to arise.

Some scientists argue that organic matter was dissolved in water ice on comets, and brought to Earth early in its history. These comets crashed into the early Earth, and deposited carbon-based molecules in copious quantities to the Earth’s surface as their water melted.

In 2014, the first space probe landed on the comet 67P/Churyumov-Gerasimenko. Suppose that scientists find the following information from 5 distinct samples after landing on the comet. Each sample was taken at a single geographical location, but 5 meters deeper than the last. Sample 1 was taken at a depth of 1 meter below the surface.

These samples were compared to 5 similar samples from the surface of Mars. Scientists posited that this comparison would be meaningful because we know that life does not exist on Mars the same way that it does on Earth. Thus, they are comparing a known non-biological celestial body, Mars, with another celestial body, the comet, which may be seeding life on suitable plants.

Which of the following facts would be most supportive of the suggestion that comets seeded organic molecules on Earth before life first developed?

The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.

Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.

The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.

Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.

Which word is defined as an object that contains mass and occupies space?

The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.

Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.

The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.

Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.

The Steady State Theory states:

Adapted from "What is Ocean Acidification?" NOAA Pacific Marine Environmental Laboratory Carbon Program. NOAA. Web. 22 Apr. 2015. http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F.

The Chemistry

When carbon dioxide is absorbed by seawater, chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals. These chemical reactions are termed "ocean acidification" or "OA" for short. Calcium carbonate minerals are the building blocks for the skeletons and shells of many marine organisms. In areas where most life now congregates in the ocean, the seawater is supersaturated with respect to calcium carbonate minerals. This means there are abundant building blocks for calcifying organisms to build their skeletons and shells. However, continued ocean acidification is causing many parts of the ocean to become undersaturated with these minerals, which is likely to affect the ability of some organisms to produce and maintain their shells.

Since the beginning of the Industrial Revolution, the pH of surface ocean waters has fallen by 0.1 pH units. Since the pH scale, like the Richter scale, is logarithmic, this change represents approximately a 30 percent increase in acidity. Future predictions indicate that the oceans will continue to absorb carbon dioxide and become even more acidic. Estimates of future carbon dioxide levels, based on business as usual emission scenarios, indicate that by the end of this century the surface waters of the ocean could be nearly 150 percent more acidic, resulting in a pH that the oceans haven’t experienced for more than 20 million years.

The Biological Impacts

Ocean acidification is expected to impact ocean species to varying degrees. Photosynthetic algae and seagrasses may benefit from higher conditions in the ocean, as they require to live just like plants on land. On the other hand, studies have shown that a more acidic environment has a dramatic effect on some calcifying species, including oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton. When shelled organisms are at risk, the entire food web may also be at risk. Today, more than a billion people worldwide rely on food from the ocean as their primary source of protein. Many jobs and economies in the U.S. and around the world depend on the fish and shellfish in our oceans.

Ocean Acidification: An Emerging Global Problem

Ocean acidification is an emerging global problem. Over the last decade, there has been much focus in the ocean science community on studying the potential impacts of ocean acidification. Since sustained efforts to monitor ocean acidification worldwide are only beginning, it is currently impossible to predict exactly how ocean acidification impacts will cascade throughout the marine food chain and affect the overall structure of marine ecosystems. With the pace of ocean acidification accelerating, scientists, resource managers, and policymakers recognize the urgent need to strengthen the science as a basis for sound decision making and action.

Over time, if ocean acidification continues at the rate projected in the passage, what would you expect to happen to the concentration of calcium carbonate in the ocean?

Adapted from "What is Ocean Acidification?" NOAA Pacific Marine Environmental Laboratory Carbon Program. NOAA. Web. 22 Apr. 2015. http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F.

The Chemistry

When carbon dioxide is absorbed by seawater, chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals. These chemical reactions are termed "ocean acidification" or "OA" for short. Calcium carbonate minerals are the building blocks for the skeletons and shells of many marine organisms. In areas where most life now congregates in the ocean, the seawater is supersaturated with respect to calcium carbonate minerals. This means there are abundant building blocks for calcifying organisms to build their skeletons and shells. However, continued ocean acidification is causing many parts of the ocean to become undersaturated with these minerals, which is likely to affect the ability of some organisms to produce and maintain their shells.

Since the beginning of the Industrial Revolution, the pH of surface ocean waters has fallen by 0.1 pH units. Since the pH scale, like the Richter scale, is logarithmic, this change represents approximately a 30 percent increase in acidity. Future predictions indicate that the oceans will continue to absorb carbon dioxide and become even more acidic. Estimates of future carbon dioxide levels, based on business as usual emission scenarios, indicate that by the end of this century the surface waters of the ocean could be nearly 150 percent more acidic, resulting in a pH that the oceans haven’t experienced for more than 20 million years.

The Biological Impacts

Ocean acidification is expected to impact ocean species to varying degrees. Photosynthetic algae and seagrasses may benefit from higher conditions in the ocean, as they require to live just like plants on land. On the other hand, studies have shown that a more acidic environment has a dramatic effect on some calcifying species, including oysters, clams, sea urchins, shallow water corals, deep sea corals, and calcareous plankton. When shelled organisms are at risk, the entire food web may also be at risk. Today, more than a billion people worldwide rely on food from the ocean as their primary source of protein. Many jobs and economies in the U.S. and around the world depend on the fish and shellfish in our oceans.

Ocean Acidification: An Emerging Global Problem

Ocean acidification is an emerging global problem. Over the last decade, there has been much focus in the ocean science community on studying the potential impacts of ocean acidification. Since sustained efforts to monitor ocean acidification worldwide are only beginning, it is currently impossible to predict exactly how ocean acidification impacts will cascade throughout the marine food chain and affect the overall structure of marine ecosystems. With the pace of ocean acidification accelerating, scientists, resource managers, and policymakers recognize the urgent need to strengthen the science as a basis for sound decision making and action.

According to the passage, why would some species benefit from ocean acidification?

Above is the deer population of Routt County National Forest between 1905 and 2005. The First White-tail deer were introduced to the forest for hunting in 1905. They are not native to the area, though they thrived in the environment.

White tailed deer eat the seeds of coniferous trees, berries, and an assortment of other plants. They tend to roam in small family herds and stick to areas where water is abundant and is unlikely to freeze completely in the winter.

In 1995, an environmental scientist watched a small herd of deer for ten days, recording their movements and taking note of herd size and stopping place. Below is a chart of his results.

What could be concluded about the larger population of white-tailed deer in Routt National Forest, given the data collected on a single herd?

The cause of the extinction of dinosaurs 65 million years ago is currently debated. Some attribute the extinction to volcanic activity while others attribute it to asteroid or comet impact. Two scientists offer conflicting viewpoints on the most probable cause of the mass extinction.

Scientist A

The extinction of dinosaurs was most likely caused by the impact of an asteroid or large comet. Unusually high levels of the rare metal iridium (found in extraterrestrial material) have been discovered in a layer of clay deposited at just the time of the extinction. In addition, this layer of clay contained quartz grains with a crystal structure that has been distorted by exceedingly high pressures (almost certainly caused by an impact). This colossal impact brought about a period of severe cooling that affected dinosaur eggs rather than adult dinosaurs. Small reptiles could survive by protecting their minute eggs in a variety of ways. However, there was no way for dinosaurs to protect their large eggs against a quickly-changing climate.

Scientist B

The extinction of dinosaurs was most likely caused by a volcanic outburst. In general, volcanic eruptions can have potent effects on climate. In 1815 the volcano Tambora in Indonesia erupted, spreading a pall of dust around the globe that resulted in killing frosts around Europe. The much larger eruption that formed the Deccan basalts about 65 million years ago would have caused a deeper and more prolonged cooling that directly affected adult dinosaurs. The rare metal iridium has been found both in active volcanoes and in a layer of clay deposited around the time of the dinosaur extinction. Therefore the dinosaurs were most likely affected by a massive volcanic eruption.

Which of the following best explains why Scientist B mentions iridium?

Scientists have recorded data in Region A, Region B, Region C and Region D. The data collected include the average daily temperature, the annual rainfall for the past year and the number of fresh water reservoirs. The scientists want to perform an experiment on wild life migration patterns.

In which region should the scientist perform their wildlife migration experiment?

The origin of the universe has been a highly debated topic among physicists. In the middle of the twentieth century, there were two prevalent models regarding the origin of the universe. The first model, called the Big Bang Theory, suggests that the universe was spontaneously created approximately 14 billion years ago. The second model, called the Steady State Theory, suggests that the universe contains no beginning or end, is always expanding, and contains a constant density.

Initially, the Big Bang Theory was widely disregarded by physicists and astronomers. In fact, the name “Big Bang” was coined by Fred Hoyle, a supporter of the Steady State Theory, who used the term in a derogatory manner. The Big Bang Theory suggests that prior to the creation of matter, a physical object that occupies space and possesses mass, the universe was filled homogenously with high-energy density and very high temperature and pressure. The universe was rapidly expanding and cooling resulting in the creation of atoms. The initial atoms that were produced were much lighter than the atoms currently found on earth, the lightest of which are hydrogen, helium, and lithium. After this initial creation of the universe, it continued to expand. The Big Bang Theory is now the prevalent theory for the origin of the universe.

The Steady State Theory suggests that there is no start or end to the universe in time or space, yet the universe is always expanding. Furthermore, the Steady State Theory states that new stars and galaxies replace old stars and galaxies and the overall appearance of the universe does not change over time.

Two sources of evidence are used to support or refute the discussed hypotheses. The first piece of data is the presence of primordial gas clouds, pockets of the universe that contain gases lighter than those found in the current universe. The second piece of evidence is that other galaxies are “red shifted”. The term red-shift indicates that as objects move farther away, the light they emit changes wavelength and appears to be more red.

A primordial gas has less mass than ________.