TOEFL Task6 実践問題 1

It’s estimated that by 2050, our population will reach 9.8 billion which is 1.6 billion more than the current population. By then, the areas that are currently used for agriculture will soon be dry due to lack of rain. In today’s lecture, I’d like to introduce two types of plants: succulents and annuals. They are expected to solve the anticipated lack of food.

Succulents are plants that store water in leaves, stems, and roots. They adapt to dry climates or soil conditions. Cacti are the most famous succulents. In general, plants lose water when they breathe through their leaves, so the bigger the surface area of their leaves, the bigger amount of water turns into steam. Cacti minimize the use of their leaves and breathe through their stems instead. Also, these plants breathe only at night to store water.

Annuals are plants that can complete their full life cycle in one growing season. Many annual plants grow from seeds, complete their life cycle quickly during the rainy season, and survive in the form of seeds in the following dry season. These plants are not affected by extreme dry conditions. Annual plants are common in semi-dry places where rainy season is of short duration.

What I have shown you may solve the possibility of food shortage in the coming years. However, we still need to look at it from different angles. Furthermore, the natural phenomena that took place in the past 40 million years could serve as an implication on how we can survive in the future.

The professor is talking about population increase and the anticipated lack of food. By then, the areas that are currently used for agriculture will soon be dry due to lack of rain. According to the professor, there are plants which are expected to solve the anticipated lack of food. The professor introduces two types of plants: succulents and annuals.

First, the professor gives an explanation about succulents that can adapt to dry climates or soil conditions. They store water in leaves, stems, and roots. Also, the professor introduces cacti as an example of a succulent and explains how they store water.

Second, the professor gives an explanation of the annuals that can complete their full life cycle in one growing season. The professor also introduces annuals as an example of plants that are common in semi-dry places where the rainy season is of short duration because they are unaffected by extreme dry conditions.

In this short lecture, I learned that succulents and annuals are unusual plants that can live in dry or semi-dry climates.

Have you ever paid attention to natural materials, the materials that can be found in plants, insects, and animals? What comes to your mind when you hear natural materials? Maybe you’re thinking of cotton, silk, and leather. These are correct, but today I’ll introduce the two strongest natural materials. The first strongest material is from plants, and the other one is from insects.

The first material is a nanofiber called nanocrystalline cellulose. It can be found in sequoia trees. A sequoia tree is usually 80 meters tall. It can carry hundreds of tons of weight and can live for 400 to 1,300 years. It is said that the nanocrystalline cellulose can bear 10 times more weight than steel. We can make strong shirts and gloves when we mix this strong material with an existing one.

In insects, cat fleas have the strongest materials in their body. It is an elastomeric protein called resilin. Resilin is a rubber-like protein and is the most flexible one in the world. When this rubber is squeezed or stretched, it will lose almost no energy. The flexible nature of resilin enables cat fleas to jump 100 times higher than their height.

If we extract these two materials’ DNA, we can create the strongest material. It can be used in cell phone cases, protective clothes, and sportswear. However, the reason why we focus on these materials is that they can improve medical items like artificial bones or artificial internal organs. Studying these materials can give people better options.

The professor is talking about materials in nature. According to the professor, these materials can be found in plants, insects, and animals. The professor introduces 2 materials as examples of materials in nature. One is nanocrystalline cellulose and the other one is resilin.

First, the professor explains that nanocrystalline cellulose is a strong material from plants. Also, the professor mentions how we can benefit from this material.

Second, the professor explains that resilin is a strong material from insects. The professor explained why cat fleas can jump high.

Through this lecture, I learned that nanocrystalline cellulose and resilin are strong materials that can be found in nature and they could improve our daily lives.