Nếu trong nguyên phân nếu thoi phân bào trong tế bào lưỡng bội (2n) không hình thành thì có thể tạo nên tế bào mang bộ nhiễm sắc thể.

A. lưỡng bội

B. đơn bội

C. tam bội.

D. tứ bội.

Read the passage and choose the best option to complete each blank.

        Any change in one part of an ecosystem can cause changes in other parts. Droughts, storms and fires can change ecosystems. Some changes ____46___ ecosystems. If there is too little rainfall, plants will not have enough water to live. If a kind of plant dies off, the animals ____47___ feed on it may also die or move away. Some changes are good for ecosystems. Some pine forests need fires for the pine trees to reproduce. The seeds are sealed inside pinecones. Heat from a forest fire melts the seal and lets the seeds ____48___. Polluting the air, soil, and water can harm ecosystems. Building dams on rivers for electric power and irrigation can harm ecosystems ____49___ the rivers. Bulldozing wetlands and cutting down forests destroy ecosystems. Ecologists are working with companies and governments to find better ways of ___50____ fish, cutting down trees, and building dams. They are looking for ways to get food, lumber, and other products for people without causing harm to ecosystems.

Điền vào số (48)

A. out    

B. in

C. go   

D. fly

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

In the West, cartoons are used chiefly to make people laugh. The important feature of all these cartoons is the joke and the element of surprise which is contained. Even though it is very funny, a good cartoon is always based on close observation of a particular feature of life and usually has a serious purpose.

Cartoons in the West have been associated with political and social matters for many years.  In wartime, for example, they proved to be an excellent way of spreading propaganda. Nowadays cartoons are often used to make short, sharp comments on politics and governments as well as on a variety of social matters. In this way, the modern cartoon has become a very powerful force in influencing people in Europe and the United States.

Unlike most American and European cartoons, however, many Chinese cartoon drawings in the past have also attempted to educate people, especially those who could not read and write. Such cartoons about the lives and sayings of great men in China have proved extremely useful in bringing education to illiterate and semi-literate people throughout China. Confucius, Mencius and Laozi have all appeared in very interesting stories presented in the  form  of  cartoons.  The  cartoons  themselves have thus served to illustrate the teachings of the Chinese sages in a very attractive way.

In this sense, many Chinese cartoons are different from Western cartoons in so far as they do not depend chiefly on telling jokes. Often, there is nothing to laugh at when you see Chinese cartoons. This is not their primary aim. In addition to commenting on serious political and social matters, Chinese cartoons have aimed at spreading the traditional Chinese thoughts and culture as widely as possible among the people.

Today, however, Chinese cartoons have an added part to play in spreading knowledge. They offer a very attractive and useful way of reaching people throughout the world, regardless of the particular country in which they live. Thus, through cartoons, the thoughts and teachings of the old Chinese philosophers and sages can now reach people who live in such countries as Britain, France, America, Japan, Malaysia or Australia and who are unfamiliar with the Chinese culture.

Until recently, the transfer of knowledge and culture has been overwhelmingly from the West to the East and not vice versa. By means of cartoons, however, publishing companies in Taiwan, Hong Kong and Singapore are now having success in correcting this imbalance between the East and the West.

Cartoons can overcome language barriers in all foreign countries. The vast increase in the popularity  of these cartoons serves to illustrate the truth of Confucius’s famous saying “One picture is worth a thousand words.”

According to the passage, which of the following is true?

A. Language barriers restricted cartoons

B. Cartoons will replace other forms of writing

C. Western cartoons always have a serious purpose

D. Cartoons can serve various purposes

Mark the letter A, B, C, or D on your answer sheet to show the underlined part that needs correction.

It is noisy enough (A) in this room, so (B) I would (C) rather you stop (D) shouting like that

A. noisy enough

B. so

C. would

D. stop

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

Learning means acquiring knowledge or developing the ability to perform new behaviors. It is common to think of learning as something that takes place in school, but much of human learning occurs outside the classroom, and people continue to learn throughout their lives.

Even before they enter school, young children learn to walk, to talk, and to use their hands to manipulate toys, food, and other objects. They use all of their senses to learn about the sights, sounds, tastes, and smells in their environments. They learn how to interact with their parents, siblings,  friends, and other people important to their world. When they enter school, children learn basic academic subjects such as reading, writing, and mathematics. They also continue to learn a great deal outside the classroom. They learn which behaviors are likely to be rewarded and which are likely to  be punished. They learn social skills for interacting with other children. After they finish school, people must learn to adapt to the many major changes that affect their lives, such as getting married, raising children, and finding and keeping a job.

Because learning continues throughout our lives and affects almost everything we do, the study of learning is important in many different fields. Teachers need to understand the best ways to educate children. Psychologists, social workers, criminologists, and other human-service workers need to understand how certain experiences change people’s behaviors. Employers, politicians,  and advertisers make use of the principles of learning to influence the behavior of workers, voters, and consumers.

Learning is closely related to memory, which is the storage of information  in  the  brain.  Psychologists who study memory are interested in how the brain stores knowledge, where this storage takes place, and how the brain later retrieves knowledge when we need it. In contrast, psychologists who study learning are more interested in behavior and how behavior changes as a result  of  a person’s experiences.

There are many forms of learning, ranging from simple to complex. Simple forms  of  learning  involve a single stimulus. A stimulus is anything perceptible to the senses, such as a sight, sound, smell, touch, or taste. In a form of learning known as classical conditioning, people learn to associate two stimuli that occur in sequence, such as lightning followed by thunder. In operant conditioning, people learn by forming an association between a behavior and its consequences (reward or punishment). People and animals can also learn by observation - that is, by watching others perform behaviors. More complex forms of learning include learning languages, concepts, and motor skills.

The passage mainly discusses _____ .

A. practical examples of learning inside the classroom

B. application of learning principles to formal education

C. general principles of learning

D. simple forms of learning