During the Pleistocene Ice Age,Group of answer choicesthe southern boundary of the North American tundra moved 20° of latitude northward.pluvial lakes dried up in Utah and Nevada, while increased rainfall farther south caused equatorial rainforests to flourish.CaCO3 shells in the world's oceans recorded a low ratio of O18 to O16.mammoths, mastodons, woolly rhinos, saber-toothed cats, and giant cave bears inhabited North America.

(Q021) During the Pleistocene Ice Age,Group of answer choicescontinental glaciers in the northern hemisphere advanced and retreated only once.sea level rose because water was tied up as ice.the continental shelf west of Alaska was exposed and allowed migration of animals and people from Asia to North America.continental glaciers covered all of North America.

Question 1- 9Around the year 1500, hunting people occupied the entire northern third of North America. They lived well from the animals with whom they shared these lands. Hunters of sea mammals had colonized the Arctic coasts of Canada and Greenland between four and five thousand years before. Land-hunting people had lived throughout much of the northern interior for at least 12,000 years. Northern North America is part of a larger circumpolar ecological (1) domain that continues across the narrow Bering Strait into Siberia and northern Europe. The overall circumpolar environment in the 1500’ s was not very different from the environment of the present. This vast landmass had a continental climate and was dominated by cold arctic air throughout a long winter and spring season. Summer temperatures ranged from near freezing to the mid-20's Celsius, while winter temperatures were often as low as 40 degrees below zero Celsius.Geographers divide the overall circumpolar domain into two zones, the Arctic and below it, the Subarctic. They refer to the landforms of these areas as tundra and taiga, respectively. Temperatures in the northern lands were below freezing for eight or nine months of the year. Subsurface soil in the Arctic's tundra remained permanently frozen. Even when summer temperatures were above freezing and the top inches of earth became (4) saturated with water, the soil below remained frozen into a permafrost, as hard as rock.When water flowed upon the surface of permanently frozen tundra, it made overland travel extremely difficult. Summer travel in the boggy lands, or muskeg country, of the Subarctic's taiga was also slow and (5) arduous. Tracking animals was more difficult than it was during the winter when the swampy ground was frozen solid and covered with snow. In both tundra and taiga, hordes of mosquitoes and biting flies bred in the (6) standing pools of water. Clothing lost its thermal efficiency when it became damp. Northern people looked forward to the turn of the season to bring the easier traveling conditions associated with cold weather. In the Arctic, they could haul food and supplies by dogsled while in the Subarctic, people could travel quickly and efficiently by snowshoes and toboggan.1. The word domain in the text is closest in meaning to Temperature Period Region Process2. Which of the following terms is used to describe the landforms of the Arctic region? Subarctic Taiga Tundra Muskeg3. For how many months of the year were temperatures below freezing in the circumpolar region? 4-5 months 6 months 8-9 months 12 months4. The word saturated in the text is closest in meaning to Enriched Dissolved Removed Soaked5. The word arduous in the text is closest in meaning to Humid Difficult Indirect Unnecessary6. The word standing in the text is closest in meaning to Not flowing Very deep Numerous Contaminated7. All of the following are mentioned as having made travel in the summer difficult EXCEPT Insects Wet clothing Swampy lands Lack of supplies8. The subsurface soil in the Arctic's tundra is most comparable to which of the following? Cement A bog A pond Sand9. Where in the passage does the author mention a means by which people traveled in the northern lands? The first sentence in paragraph 1 The first sentence in paragraph 2 The last sentence in paragraph 2 Paragraph 3

Paragraph5: Milankovitch attributed the onset of the Pleistocene Ice Age to variations in threeparameters of Earth's orbit. The first of these is orbital eccentricity, which is the degree that Earth'sorbit departs from a perfect circle in its orbit around the Sun. The orbit varies from nearly a circle toan ellipse (an oval-shaped, elongated circle) and back again in about 100,000 years. Thiscorresponds closely to 20 warm-cold climatic cycles that occurred during the Pleistocene. Thesecond parameter is the angle between Earth's axis and a line perpendicular to the plane of theecliptic (the path along which the Sun appears to move). This angle shifts about 1.5 degrees duringa 41,000-year cycle. The third parameter relates to another complicated movement pattern with a23,000-year cycle. Milankovitch proposed, and now many scientists agree, that the interaction ofthese three parameters provided the triggering mechanism for the glacial-interglacial episodesduring the Pleistocene.5. The word “this” in the passage refers toA: the variation in three parameters of Earth’s orbitB: the amount of time it takes for Earth to orbit around the SunC: the length of the Pleistocene AgeD: the variation of Earth’s orbit from a circle to an ellipse and back to a circle

What happened during the Pleistocene to cause global cooling?low solar activityfossil fuel consumptionbreakup of Pangaeaa shift in earth’s orbit

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