A: It has been extremely difficult for scientists to identify the causes of glaciation because most iceages occurred millions of years ago and left behind little geologic record.B: Some scientists have noted similarities between long-term and short-term climatic cycles of thePleistocene.C: Changes within the Sun itself are known to have a major influence on the amount of solarradiation received at any given latitude on Earth.D: Long-term glaciation is most likely caused by the movement and interaction of Earth's plates.E: The Milankovitch theory uses variations in Earth's rotation and orbit to explain the cyclicoccurrence of glacial periods that last tens to hundreds of thousands of years.F: Volcanic activity and variations in solar energy have been proposed but not established ascauses of climatic events that are hundreds of years long. It has been extremely difficult forscientists to identify the causes of glaciation because most ice ages occurred millions of years agoand left behind little geologic record.

A particularly interesting hypothesis for intermediate-term climatic events was putforward by the Serbian astronomer Milutin Milankovitch during the 1920s. He proposed that minorirregularities in Earth's rotation and orbit are sufficient to alter the amount of solar radiation theEarth receives at any given latitude, and hence can affect climatic changes. Now called theMilankovitch theory, the hypothesis was initially ignored but has received renewed interest duringthe past 20 years.4. According to paragraph 4, the Milankovitch theory proposes which of the following?A: Climatic change occurs when irregularities in Earth's orbit and rotation take place at the sametime that the amount of solar radiation reaching the Earth decreases.B: The amount of solar radiation reaching Earth at any given latitude varies throughout the year,causing climatic change.C: Slight variations in Earth's orbit and rotation can affect the climate by changing the amount ofsolar radiation received by Earth at any given latitude.D: Climatic change occurs when changes in the amount of solar radiation received by Earth aregreat enough to alter Earth's orbit and rotation

Climatic events having durations of several centuries, such as the Little Ice Age, aretoo short to be accounted for by plate tectonics or Milankovitch cycles. However, severalhypotheses have been proposed to explain these shorter events, including variations in solarenergy and volcanism. Variations in solar energy could result from changes within the Sun itself orfrom anything that would reduce the amount of energy Earth receives from the Sun. The lattercould be caused by the solar system passing through clouds of interstellar dust and gas or bysubstances in the atmosphere reflecting solar radiation back into space. Records kept over the past75 years indicate that during this time the amount of solar radiation has varied only slightly. Soalthough variations in solar energy may influence short-term climatic events, such a correlation hasnot been demonstrated.6. According to paragraph 6, processes such as plate tectonics and Milankovitch cyclescould not be responsible for the Little Ice Age becauseA: climatic events over the past several centuries were not severe enough to have been caused bysuch processesB: such processes only apply to climatic events that occurred during the PleistoceneC: recent studies demonstrate that the Little Ice Age was caused by variations in solar energy andvolcanismD: such processes operate too slowly to be responsible for short-term climate change

Only a few periods of extensive glaciation lasting millions of years are recognized inthe geologic record, each separated from the others by long intervals of mild climate. Suchlong-term climatic changes probably result from slow geographic changes related to plate-tectonicactivity (the movement and interaction of the pieces of Earth's outer layer, called plates). Movingplates can carry continents to high latitudes where glaciers can exist, provided that these latitudesreceive enough precipitation as snow. Plate collisions, the Subsequent uplift of vast areas farabove sea level, and the changing atmospheric and oceanic circulation patterns caused by thechanging shapes and positions of plates also contribute to long-term climate change.1. According to paragraph 2, plate-tectonic activity may contribute to long-term climatechange in all of the following ways EXCEPTA: by moving continents to different geographic locationsB: by increasing precipitation in low latitudesC: by lifting landmasses to higher elevationsD: by causing changes in air- and ocean-flow patterns

A theory explaining ice ages must also address the fact that during the Pleistocene IceAge (2.6 million to 11,700 years ago) several intervals of glacial expansion separated by warmerinterglacial periods occurred. At least four major episodes of glaciation have been recognized inNorth America, and six or seven glacial advances and retreats occurred in Europe. Theseintermediate-term climatic events took place on timescales of tens to hundreds of thousands ofyears. The cyclic nature of this most recent episode of glaciation (i.e., during the Pleistocene) haslong presented a problem in formulating a comprehensive theory of climatic change.2. The word “comprehensive ”in the passage in meaning toA: complete B: convincing C: well supported D: widely accepted3. According to paragraph 3, which of the following is a fact that theories about ice ageshave had difficulty explaining?A: The Pleistocene was separated from the previous ice age by a long interval of mild climate.B: During the Pleistocene Ice Age, glacial advances and retreats alternated in a cyclic pattern.C: There have been notably fewer episodes of glaciation in North America than in Europe.D: The Pleistocene Ice Age gave way to milder climate about 10,000 years ago.

(Q001) Which of the following is accurate about Louis Agassiz?Group of answer choicesHe stated that there are changes in the amount and distribution of insolation received on the Earth.He stated that there are cyclical changes in the Earth's orbit and axial tilt.He stated that the presence of erratics in Europe was due to large continental ice sheets.He offered ideas that explain the timing of ice-age events but not the severity of temperature change associated with ice ages.