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 following questions.

Plants are subject to attack and infection by a remarkable variety of symbiotic species and have evolved a diverse array of mechanisms designed to frustrate the potential colonists. These can be divided into preformed or passive defense mechanisms and inducible or active systems. Passive plant defense comprises physical and chemical barriers that prevent entry of pathogens, such as bacteria, or render tissues unpalatable or toxic to the invader. The external surfaces of plants, in addition to being covered by an epidermis and a waxy cuticle, often carry spiky hairs known as trichomes, which either prevent feeding by insects or may even puncture and kill insect larvae. Other trichomes are sticky and glandular and effectively trap and immobilize insects. If the physical barriers of the plant are breached, then preformed chemicals may inhibit or kill the intruder, and plant tissues contain a diverse array of toxic or potentially toxic substances, such as resins, tannins, glycosides, and alkaloids, many of which are highly effective deterrents to insects that feed on plants. The success of the Colorado beetle in infesting potatoes, for example, seems to be correlated with its high tolerance to alkaloids that normally repel potential pests. Other possible chemical defenses, while not directly toxic to the parasite, may inhibit some essential step in the establishment of a parasitic relationship. For example, glycoproteins in plant cell walls may inactivate enzymes that degrade cell walls. These enzymes are often produced by bacteria and fungi. Active plant defense mechanisms are comparable to the immune system of vertebrate animals, although the cellular and molecular bases are fundamentally different. Both, however, are triggered in reaction to intrusion, implying that the host has some means of recognizing the presence of a foreign organism. The most dramatic example of an inducible plant defense reaction is the hypersensitive response. In the hypersensitive response, cells undergo rapid necrosis ― that is, they become diseased and die ― after being penetrated by a parasite ; the parasite itself subsequently ceases to grow and is therefore restricted to one or a few cells around the entry site. Several theories have been put forward to explain the bases of hypersensitive resistance. 

What does the passage mainly discuss?

Cụm từ "subject to" ở dòng 1 có ý nghĩa gần nhất với

A. hấp dẫn                  B. tăng cường bởi                   C. được phân loại bởi             D. phải chịu

subject to (a): dễ bị, phải chịu, khó tránh khỏi

=> subject to = susceptible to

Dẫn chứng: Plants are subject to attack and infection by a remarkable variety of symbiotic species and have evolved a diverse array of mechanisms designed to frustrate the potential colonists.

Chọn đáp án là D

Từ "puncture" trong dòng 8 có nghĩa gần nhất với______

A. bao quanh              B. nhúm                      C. xuyên qua               D. bao gồm

puncture (v): đâm thủng

=> puncture = pierce

Dẫn chứng: The external surfaces of plants, in addition to being covered by an epidermis and a waxy cuticle, often carry spiky hairs known as trichomes, which either prevent feeding by insects or may even puncture and kill insect larvae.

Chọn đáp án là C

Từ "which" trong dòng 13 đề cập đến

A. rào cản                   B. mô                          C. chất                         D. côn trùng

Dẫn chứng: If the physical barriers of the plant are breached, then preformed chemicals may inhibit or kill the intruder, and plant tissues contain a diverse array of toxic or potentially toxic substances, such as resins, tannins, glycosides, and alkaloids, many of which are highly effective deterrents to insects that feed on plants.

Chọn đáp án là C

Các chất sau đây tác giả đề cập đến như là không độc đối với bọ cánh cứng Colorado?

A. Alkaloids               B. Glycosides              C. Nhựa                      D. taninin

Dẫn chứng: The success of the Colorado beetle in infesting potatoes, for example, seems to be correlated with its high tolerance to alkaloids that normally repel potential pests.

Chọn đáp án là A

Tại sao tác giả đề cập đến "glycoproteins" trong dòng 17?

A. Để minh họa hóa chất hoạt hóa trong phòng vệ thực vật

B. Để nhấn mạnh tầm quan trọng của các rào cản vật lý trong phòng vệ thực vật

C. So sánh cơ chế phòng vệ thực vật với hệ miễn dịch của động vật

D. Giới thiệu việc thảo luận về các cơ chế phòng vệ chủ động trong thực vật

Dẫn chứng: For example, glycoproteins in plant cell walls may inactivate enzymes that degrade cell walls.

These enzymes are often produced by bacteria and fungi.

Chọn đáp án là A

Ở đâu trong đoạn văn, tác giả miêu tả một phản ứng phòng vệ thực vật chủ động?

A. Dòng 1-3                B. Dòng 13-15                        C. Dòng 19-23            D. Dòng 4-6

Dẫn chứng: Active plant defense mechanisms are comparable to the immune system of vertebrate animals, although the cellular and molecular bases are fundamentally different. Both, however, are triggered in reaction to intrusion, implying that the host has some means of recognizing the presence of a foreign organism. The most dramatic example of an inducible plant defense reaction is the hypersensitive response.

Chọn đáp án là C

Đoạn văn có thể tiếp tục bàn về giả thuyết gì?

A. Cơ sở của việc phòng vệ thực vật

B. Các nguyên tắc của phản ứng quá mẫn.

C. Các chất hoá học ức chế mối quan hệ ký sinh trùng.

D. Làm thế nào để thực vật tạo ra hóa chất độc hại.

Dẫn chứng: Several theories have been put forward to explain the bases of hypersensitive resistance.

Chọn đáp án là B