Lesson 2 （找主干）
Q1：
Two species of deer have been prevalent in the Puget Sound area of Washington State in the Pacific Northwest of the United States.
Q2：
David Douglas found a disturbing change in the animal life around the fort during the period between his first visit in 1825 and his final contact with the fort in 1832.
Q3：
The source of Roman obsession with unity and cohesion may well have lain in the pattern of Rome’s early development.
Q4：
The gradual drying of the soil caused by its diminished ability to absorb water results in the further loss of vegetation, so that a cycle of progressive surface deterioration is established.
Q5：
The sheer scale of the investment that it took to begin commercial expansion at sea reflects the immensity of the profits that such trade could create.
Q6：
In the central deeper part of the basin, the last of the brine evaporated to precipitate more soluble sodium chloride (salt).
Q7：
Later, under the weight of overlying sediments, this salt flowed plastically upward to form salt domes. Before this happened, however, the Mediterranean was a vast desert 3,000 meters deep.
Q8：
Even diluted by the terrestrial material excavated from the crater, this component of meteorites is easily identified.
Q9：
In 1969 he crossed the Atlantic in an Egyptian-style reed boat to prove Egyptian influences in the Americas.
Q10：
Vast areas along the coast may have been deglaciated beginning around 16,000 years ago, possibly providing a coastal corridor for the movement of plants, animals, and humans sometime between 13,000 and 14,000 years ago.
Q11：
Many complex factors led to the adoption of the new economies, not only at Abu Hureyra, but at many other locations such as Ain Ghazal, also in Syria, where goat toe bones showing the telltale marks of abrasion caused by foot tethering (binding) testify to early herding of domestic stock.
Q12：
American paleontologists David Raup and John Sepkoski, who have studied extinction rates in a number of fossil groups, suggest that episodes of increased extinction have recurred periodically, approximately every 26 million years since the mid-Cretaceous period.
Q13：
In the wake of the Roman Empire’s conquest of Britain in the first century A.D., a large number of troops stayed in the new province, and these troops had a considerable impact on Britain with their camps, fortifications, and participation in the local economy.
Q14：
Therefore, when observational assessment is used as a technique for studying infant perceptual abilities, care must be taken not to overgeneralize from the data or to rely on one or two studies as conclusive evidence of a particular perceptual ability of the infant.
Q15：
In the second case, pollinators (insects, birds) obtain food from the flowering plant, and the plant has its pollen distributed and seeds dispersed much more efficiently than they would be if they were carried by the wind only.
Q16：
This scenario begins with the planting of hyperaccumulating species in the target area, such as an abandoned mine or an irrigation pond contaminated by runoff.
Q17：
Contrary to the arguments of some that much of the Pacific was settled by Polynesians accidentally marooned after being lost and adrift, it seems reasonable that this feat was accomplished by deliberate colonization expeditions that set out fully stocked with food and domesticated plants and animals.
Q18：
But as more and more accumulations of strata were cataloged in more and more places, it became clear that the sequences of rocks sometimes differed from region to region and that no rock type was ever going to become a reliable time maker throughout the world.
Q19：
Many plants and animals disappear abruptly from the fossil record as one moves from layers of rock documenting the end of the Cretaceous up into rocks representing the beginning of the Cenozoic (the era after the Mesozoic).
Q20：
There appear to be many unexplored matters about the motivation to reflect — for example, the value of externally motivated reflection as opposed to that of teachers who might reflect by habit.
