Questions 29 through 34.
Listen to part of a lecture in a botany class. The professor is talking about seeds.
Our study of the life cycle of a plant usually starts with the germination of a seed. The seed contains the hereditary information the plant needs to grow. It also contains enough food to nourish itself during germination.
Related Posts maybe you like:
- TOEFL IBT Listening Practice Test 12 Solution, Explanation & Transcripts
- TOEFL IBT Listening Practice Test 11 Solution, Explanation & Transcripts
- TOEFL IBT Listening Practice Test 10 Solution, Explanation & Transcripts
- TOEFL IBT Listening Practice Test 09 Solution, Explanation & Transcripts
- TOEFL IBT Listening Practice Test 08 Solution, Explanation & Transcripts
Heredity—the genes inherited from the parent plant— decides several things about the life of the plant. Heredity determines what the plant will look like, how it will grow, and what kind of seeds it will bear. Inside the seed is all the genetic information the plant needs to grow to maturity. An individual plant’s survival depends partly on its hereditary characteristics. But a plant depends on more than just heredity. It needs the outside world to supply its daily needs: sunlight, carbon dioxide, nutrients, and water.
Some seeds germinate as soon as they’re in a suitable environment. Other seeds remain dormant and won’t germinate until a specific environmental cue causes them to “wake up” and come out of dormancy. Seeds of desert plants germinate only after a heavy rainfall. If they germinated after a slight rain, the soil might soon be too dry to support the seedlings. Seed dormancy increases the chances that germination will take place at a time and place that are best for the seedling.
Germination begins when water penetrates the seed’s outer coating and reaches inside to the live embryo. Water is a basic requirement, and no seed will germinate unless it absorbs water. This is because the embryo inside the seed is dehydrated, and cells need water for active metabolism. Water is the substance in which most of the chemical reactions of the plant take place.
For a seed to sprout and grow, it needs a great deal of energy. Seeds get this energy by converting the energy of their stored fuel molecules, and this requires oxygen. Germination also requires a certain combination of temperature and light, which, in North America, is triggered by the start of spring. Some seeds respond early in the season, others much later.
Each plant species has an ideal temperature at which the largest number of seeds will germinate.
When the embryo takes in water, it often swells to several times its original size. It gets this first burst of energy by tapping its own food stores. Eventually, the seed expands enough to rupture its coating and burst through the seed case.
The first organ to emerge from the germinating seed is the embryonic root. The root pushes outward into the soil and anchors the seedling. Now the seedling begins to gather up water and nutrients through thousands of tiny hair–like roots. After a certain period, the seedling sprouts upward. The tip of the shoot has to break through the soil surface. Light is the environmental cue that tells the seedling when it’s broken ground. Only when the seedling senses light will it straighten up and begin to grow taller. As it straightens up and grows, it unfolds its solar collectors, its first leaves. Once the seedling has its main leaves, it doesn’t need its embryonic food stores anymore because now it draws most of its growth energy directly from the sun.
The germination of a seed is a critical stage in the plant’s life cycle. The tough seed becomes a fragile seedling, and only a small fraction of seedlings survive long enough to become parent plants. Because the chances of a seedling’s survival are so low, plants make up for this by producing enormous numbers of seeds.
Questions 35 through 39.
Listen to a conversation between a student and a professor.
M:Hi, Professor Barker.
W:Hello, Sam. How are you?
M:OK, I guess. Um, did you get a chance to read the draft of my term paper yet?
W:Yes, I’ve looked at it. It’s is about organizational redesign, right?
M:Yeah, that’s right.
W:Let’s see … here it is. All right. OK. You … uh … you start out by defining organizational redesign.
M:Right. It’s changing the goals, responsibilities, and relationships within an organization.
W:Right. That’s a good way to begin. All right, then … let’s see … you talk about how inappropriate organizational designs can create severe problems. The introduction is OK. Everything you say is clearly relevant. The body of your paper is where you start to stray a bit. Basically, you’re trying to do too much. You introduce a lot of threads … and then don’t develop all your ideas.
M:Oh. Could you, uh, maybe be more specific?
W:Sure. Uh, for example, here you summarize Peterson’s four steps for managers to follow in organizational redesign. And then you list Roswell’s plan, and then you also describe Jordan and his six–point plan. What you end up with is lots of ideas, some of them overlapping and duplicating each other. What you need to do is narrow this down to the three or four … or five steps that you believe are necessary for redesigning an organization. Do you see what I mean?
M:Uh, I think so.
W:It would also be good to illustrate your points with examples from a real organization, for example, a case study of a company that’s successfully redesigned itself. You need to make this real.
M: Mm-hmm. I see what you mean. I need to show how redesign actually works in the real world. I actually thought of an example, but I don’t know if it’s right for this paper. It’s a nursery business—you know, they grow plants and flowering shrubs and things. It’s a business I actually know. My uncle is the superintendent there.
W:And the nursery has a performance problem that needs attention?
M:Sort of. My uncle was telling me about some changes he’d like to see in the business. I don’t know … it’s just an idea … maybe it would work here.
W:It sounds like it might be an idea worth pursuing.
W:So, to recap what we said. You need to focus on three or four essential steps for organizational redesign and then illustrate them with a real-world example of what a real business could do, or has done, along these lines. Does that make sense?
M:Yes, it does. This helps me a lot. Thanks for your time.
Questions 40 through 45.
Listen to part of a lecture in a geography class. The professor is talking about the Northwest Passage.
It was the promise of wealth that first drew European powers to look for a westward route to Asia. It was wealth rather than the idea of a New World that drove Columbus and other Europeans to search for a western route to China and Japan. However, they soon realized that the North American continent was a barrier to progress. So, they began to search for a way around the northern edge of the continent, a Northwest Passage that would link the Atlantic to the Pacific. For the next 500 years, they nudged their ships through the Arctic waters, looking for the Northwest Passage.
In the sixteenth century, the Spanish, Portuguese, French, and English all sent expeditions to the northern shores of North America. They were all driven back by the ice. The Englishman Martin Frobisher spent several years exploring what is now Canada and searching for wealth in the Arctic. He made three voyages in scarch of the Northwest Passage, and he did reach the mouth of the passage, but stopped when he found what he thought was gold. This “gold” turned out to be iron ore. In 1607, Henry Hudson began his exploration of the Canadian Arctic. He discovered the bay that later became Hudson Bay, but the voyage ended in tragedy when the crew rebelled. The Northwest Passage wasn’t crossed until almost 300 years later, when a Norwegian explorer completed the trip in three years.
The Northwest Passage is actually a number of possible routes through a deadly maze of sea ice, narrow straits, and oddly shaped islands. Today, icebreakers can follow the passage with ease, but to attempt it without this technology still requires a great deal of courage. Depending on ice conditions, one route might be open while another is blocked. The passage changes from year to year, and even from week to week.
In the summer of 2000, a Canadian Mountie took a large patrol boat into the heart of the Northwest Passage. He expected to encounter ice, but to his surprise, there were no bergs, no growlers, and no pancake ice. In fact, he found no ice at all. For the past few summers now, vast stretches of the Northwest Passage have been free of ice. The departure of the ice is the result of natural, long-term atmospheric patterns that have warmed the Arctic in recent decades and also of the heating of the planet by greenhouse gases.
In the Arctic, temperatures have risen 3 to 4 degrees. That small difference has changed the landscape for thousands of miles. The ice has disappeared at a rate of about 3 percent each decade since the 1970s, and ice sheets that used to be ten feet thick are now less than six feet from top to bottom. Climate experts now predict that, in 50 years or less, the passage will be free of ice throughout the summer. Canadian officials say it’s only a matter of time before all kinds of ships—everything from supertankers to sailboats—will start crossing these once impassable waters.
There are potential consequences to shipping in the passage. Ships could disrupt the polar bears and bowhead whales that live there. There could be an increase in the smuggling of polar bear hides and walrus tusks. An increase in the number of tourists could mean an increase in the amount of trash they leave behind. The biggest concern, however, is the threat of an oil spill from a supertanker. An oil spill would damage this pristine region and be extremely difficult to clean up.
Questions 46 through 51.
A historian has been invited to speak to an architecture class. The class has been studying the history of domestic architecture. Listen to part of the talk
In New England today, around eighty houses that were built in the seventeenth century are still standing. Many of these houses and the documents relating to them have been thoroughly studied and some of the houses have been carefully restored to their original condition. These early houses of New England are the greatest single source of knowledge about domestic architecture of the seventeenth century, particularly about details of plan and construction.
All seventeenth-century houses were not alike. There was some variety in their floor plans, with each house being shaped by the circumstances of the family and the characteristics of the site. Nevertheless, it’s possible to identify the three most common plan types, which were the one-room plan, the two- room plan, and the added lean to plan. We can even figure out the order in which they probably evolved.
The one-room plan was the simplest and the earliest design. It was used in the early cottages at Plymouth and Salem, dating back to the 1620s, and it remained common in smaller and poorer dwellings throughout the century. In the one-room plan, the front door opened into a small entry room, which was then called the “porch.” In the porch, there was a steep staircase built up against a massive chimney. The large main room was a combination living-dining cooking room called the “hall.” In this room, there was a huge fireplace set into the chimney mass. The staircase in the porch led to one large sleeping room upstairs.
The second house design was the two room plan, which was simply the one-room plan with a parlor added at the other side of the chimney and porch. The result was a house with two fireplaces, one in the hall and one in the parlor, that were set back to- back in the central chimney structure. In several earlier examples of this design, the parlor was actually built onto an older one-room house, enlarging the smaller house.
But more common in later examples, both rooms were built at the same time when families could afford it. Upstairs, there were two sleeping rooms, called the “hall chamber” and the “parlor chamber.” after the room below each.
The third design, die added lean-to plan, was the result of an addition at the back of the house, making this the largest of the three plans. The lean-to addition had roof rafters leaning against the second-story w all of the main house. The added space was used as a kitchen. The cooking was done in a fireplace added to the back of the central chimney structure. There were two more rooms built on either side of the kitchen. On the cold side of the kitchen, there was a pantry for food storage, and on the warm side, facing the sun on the south, there was a bedroom. Above the kitchen, under the lean-to roof, there was attic space for storage or more sleeping rooms, which you reached by a staircase leading up from the kitchen.
These three house plans form a logical evolutionary sequence. The one-room plan was the earliest design. Then the two-room plan was most common up until around 1650.
By the year 1700, the lean-to plan was dominant. However, it’s important to note that the one room plan although it came earliest continued to be built throughout the seventeenth century. So, it’s best not to try to determine the age of a colonial house strictly by its plan type, which is not a perfect indicator of the house’s age.