PTE Retell Lecture practice: 12 lectures with answers

Plate tectonics is the scientific theory that describes the large-scale movement of Earth's lithosphere. The lithosphere is broken into several rigid plates that float on the semi-fluid asthenosphere beneath them. There are three main types of plate boundaries. First, divergent boundaries occur where plates move away from each other. This process allows magma to rise from the mantle, creating new oceanic crust. The Mid-Atlantic Ridge is a classic example of a divergent boundary. Second, convergent boundaries happen where plates collide. Depending on the type of crust involved, one plate may be forced beneath the other in a process called subduction, which can generate deep ocean trenches and volcanic arcs. When two continental plates collide, they form large mountain ranges like the Himalayas. Third, transform boundaries exist where plates slide horizontally past one another. The friction along these boundaries can cause powerful earthquakes, as seen along the San Andreas Fault in California. Understanding plate tectonics is essential for predicting earthquakes, understanding volcanic activity, and reconstructing the geological history of our planet.

Now, you might think it strange that in a lecture on biology, I will be talking a lot about mathematics... urn ... If I may digress a bit ... When I was a student, mathematics, the language of dear abstraction, had nothing to do with life sciences like biology, the sphere of messy organic forms, cutting up frogs in the lab, and so on... um ... In fact, I started doing biology precisely to avoid matlls and physics. So, I've had a lot of catching up to do. We are all aware of how the sciences have come to inter-relate more and more, and not only will mathematics impinge more and more on biology but also, I am told, in the 21" century, the driving force behind mathematics will be biology. This is partly because mathematicians are always on the look out for more areas to conquer. But a far greater reason is that the subject has been boiled down to physics and chemistry - obvious attractions for mathematicians.A number of mathematical fields can be applied to biology. For example, knot theory is used in the analysis of the tangled strands of DNA, and abstract geometry in four or more dimensions is used to tell us about viruses. Again, neuroscience appears to be mathsfriendly and equations can also explain why hallucinogenic drugs cause the users to see spirals. So, if mathematicians are taking such a keen interest in biology, the least we can do as biologists is return the compliment.

Let's talk about an economic model that is gaining traction around the world: the circular economy. Traditionally, our economy has been linear. We take raw materials from the earth, make products, use them, and then throw them away. This linear model is wasteful and unsustainable. A circular economy, on the other hand, is regenerative by design. It aims to decouple economic growth from the consumption of finite resources. The core principles are to eliminate waste and pollution, keep products and materials in use, and regenerate natural systems. How does this work in practice? Instead of buying a washing machine, you might lease it from a manufacturer. When the machine reaches the end of its life, the manufacturer takes it back, recovers the valuable materials, and uses them to build new machines. Another example is in the electronics industry, where companies are designing modular smartphones that can be easily repaired and upgraded, reducing electronic waste. Food waste can be composted to enrich soil, closing the nutrient loop. The circular economy is not just about recycling; it is about rethinking the entire lifecycle of products. Businesses that adopt circular principles can reduce costs, create new revenue streams, and build resilience against resource price volatility. It represents a fundamental shift in how we produce and consume.

Mountains are not just beautiful landscapes; they are the result of immense geological forces acting over millions of years. The primary process that builds mountains is plate tectonics. When two tectonic plates collide, the immense pressure causes the Earth's crust to buckle, fold, and thrust upward. This is called orogeny. The Himalayan mountain range, for example, began forming around fifty million years ago when the Indian plate collided with the Eurasian plate. That collision is still ongoing, which is why the Himalayas continue to rise slowly each year. Another way mountains form is through volcanic activity, where magma pushes up through the crust and accumulates over time. Volcanic mountains like Mount Fuji in Japan are created this way. Fault-block mountains, such as the Sierra Nevada in the United States, form when large blocks of the Earth's crust are lifted along fault lines. Regardless of the specific mechanism, mountain building is a slow and powerful process that shapes the planet's surface and influences weather patterns, ecosystems, and human settlement.

In this global village, 'Cultural Empathy' emerges as a beacon of unity amidst our diverse backgrounds. It is the heartfelt understanding that the world is a mosaic of cultures, each piece as significant as the other. Encountering a culture different from our own can be like stepping into a new world. It's the subtle art of listening and the quiet humility of learning that bridges the gap. When we travel or interact with international students, we're not just exchanging words; we're sharing pieces of our heritage. Moreover, cultural empathy extends beyond mere tolerance. It's about celebration and participation. It's one thing to acknowledge festivals from around the world; it's another to dance to the rhythm of foreign melodies and taste the spice of exotic cuisines. This is how we weave the threads of understanding and respect into the fabric of our everyday lives. Let us, as students and future leaders, champion the cause of cultural empathy, for it is the path to a more cohesive, compassionate, and peaceful world.

Our society is just more and more mobile. Everything is on the move. I mean, the good part, it’s convenient. You can drink coffee anywhere. You don’t have the stay in the dinner. It can be in the subway. You can be walking. The bad part is it’s harder to savor a coffee when you’re taking it on the road. The first patent for a lid on a cup was in 1934, but it was for cold beverages, and in 1950 this guy names James Reifsnyder invented the first snap-on lid, but it didn’t have an opening for drinking. In the ’60s there was this huge cultural shift where people started drinking coffee on the move, and 7-Eleven was the first to sell coffee to go. And then came this revolution. In 1967, a man named Alan Frank invented a lid that you could peel a tab off, like in the shape of a guitar pick and drink it from there. In 1975, another big advance, you could peel back a tab and attach it to the lid itself. So more and more people started drinking coffee on the go. In 1984, a watershed moment in the history of coffee cup lids, the birth of the traveler lid, and it is iconic. You’ve seen it a million times, and it solved a whole host of problems. It’s designed so that you don’t splash your face, because it’s higher than any of the other ones. It’s got this protruding rim, so it slightly cools the coffee before it hits your lips. It’s got a small depression in the center for your nose, so you can really get in there and get maximum aroma. It’s got this tiny air hole that lets the steam out and stops it from creating a vacuum. This is one of those objects where you just don’t notice it until it dribbles on your lap, so I think the coffee cup lid will just continue to evolve, and you’re gonna see a move away from single-use plastic lids to lids that are a little more sustainable.

Climate change, some adverse effects of climate changes to agricultural productions. Some lands are unsuitable for growing crops. There will be millions of people facing hunger in Africa in the future. Climate change will result in less production and less food. It is difficult for developing countries to deal with climate change due to their financial status and other issues. There are many people living in hunger especially in Africa. The climate change has devastating effects on world economy. The tropical areas on earth are dry and hot, and are originally not suitable for food production. The change of the climate leads to extreme weather conditions such as flood and hurricane, which exacerbates the food production. As a result, it leads to a continuous decline in food supply annually around 10-17%. And this trend is perceived to be continue in the future by 2070. The regions suffering the most will be some African countries.

All of my research, and, that I conducted was my 60 plus graduate students, was motivated by their need to learn, so that we can teach. Of course, um, some inventions happened along the way but I've always considered the end, the result. And I always consider these inventions to be byproduct, byproducts of the learning process. The end product for me was always better understanding or when one really succeeded in unifying theory that can help us in teaching the subject. I've also looked at teaching as a vehicle to try new ideas, of new ways to doing things on an intelligent group of learners. That is as the vehicle for the teaching research results. And in my experience, this kind of teaching is the most stimulating and motivating to students. I've also uncovered many interesting research problems in the course of teaching assumption. It is this unity of research and teaching, their close connection, and the benefits garnered by exercising and the interplay that to me characterizes the successful professor.

Reliability and validity are two essential concepts for comprehending standardized tests. To grasp their distinction, we can use the analogy of two faulty thermometers. An unreliable thermometer gives a different reading every time you measure your temperature, while a reliable but invalid thermometer is consistently ten degrees too high. Validity also hinges on correct interpretations of outcomes. If people claim test results signify something they don't, that test may suffer from a validity issue. Just as we wouldn't expect a ruler to reveal an elephant's weight or its breakfast, we can't expect standardized tests alone to reliably indicate how intelligent someone is, how diplomats will manage a tough scenario, or how courageous a firefighter might prove to be. Thus, standardized tests can help us learn a little about many people quickly, but they typically can't tell us a lot about a single individual. Many social scientists are concerned that test scores lead to broad and often detrimental changes for test-takers, sometimes with lasting life impacts. We can't fault the tests, however. It's our responsibility to use the appropriate tests for the appropriate purposes and to interpret results correctly.

Today we will practice assessing the primary instrument used when speaking to groups—the voice. Three key elements combine to produce either a favorable or unfavorable experience for audiences. They can result in a voice that is pleasant to hear and can be employed effectively. Or they can produce a voice that fails to capture attention, or worse, triggers a negative response. The three elements are volume, pitch, and pace. When assessing volume, remember that an effective speaker adjusts to the dimensions of both the room and the audience. Naturally, with an amplification tool like a microphone, the speaker can use a relaxed tone. But speakers should not rely entirely on microphones; a skilled speaker can project loudly without yelling. The second element, pitch, concerns the highness or lowness of sounds. High pitches are generally harder for most people to listen to, so speakers should typically use the lower ranges of their voice. During a talk, it is crucial to vary pitch somewhat to sustain interest. The third element, pace, which refers to how quickly or slowly words and sounds are spoken, should also be varied. A slower pace can be used to highlight key points. Note that the moments spent silent can be significant as well. Pauses should be used to indicate transitions or build anticipation. Because a pause allows listeners time to reflect on what was just said or even to guess what might come next, it can be highly effective when shifting from one subject to another. What I want you to do now is watch and listen to a video and use the forms I provided to evaluate the speaking voices you hear. Then tonight, I want you to go home and read a passage into a recorder and assess your own voice.

There are two major factors that cause food to go bad: microbes and oxidation. Microbes like bacteria and fungi invade food and feed off its nutrients. Some of these can cause diseases, like listeria and botulism. Others just turn edibles into a smelly, slimy, moldy mess. Meanwhile, oxidation is a chemical change in the food’s molecules caused by enzymes or free radicals which turn fats rancid and brown produce, like apples and potatoes. Preservatives can prevent both types of deterioration. Before the invention of artificial refrigeration, fungi and bacteria could run rampant in food. So we found ways to create an inhospitable environment for microbes. For example, making the food more acidic unravels enzymes that microbes need to survive. And some types of bacteria can actually help. For thousands of years, people preserved food using bacteria that produce lactic acid. The acid turns perishable vegetables and milk into longer lasting foods, like sauerkraut in Europe, kimchi in Korea, and yogurt in the Middle East. These cultured foods also populate your digestive track with beneficial microbes. Many synthetic preservatives are also acids. Benzoic acid in salad dressing, sorbic acid in cheese, and propionic acid in baked goods.

Community service is an important component of education here at our university. We encourage all students to volunteer for at least one community activity before they graduate. A new community program called "One On One" helps elementary students who've fallen behind. Your education majors might be especially interested in it because it offers the opportunity to do some teaching, that is, tutoring in math and English. You'd have to volunteer two hours a week for one semester. You can choose to help a child with math, English, or both. Half-hour lessons are fine, so you could do a half hour of each subject two days a week. Professor Dodge will act as a mentor to the tutors. He'll be available to help you with lesson plans or to offer suggestions for activities. He has office hours every Tuesday and Thursday afternoon. You can sign up for the program with him and begin the tutoring next week. I'm sure you'll enjoy this community service and you'll gain valuable experience at the same time. It looks good on your resume, too, showing that you've had experience with children and that you care about your community. If you'd like to sign up, or if you have any questions, stop by Professor Dodge's office this week.