Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered...
Đề bài
Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 22 to 26.
Vaccines train the immune system to recognize and fight harmful pathogens. Most vaccines introduce a harmless version of the virus or bacteria, prompting the body to produce antibodies. (22) _______. These antibodies stay in the system, ready to respond quickly if the real threat appears. Scientists often use weakened or inactive forms of the virus to trigger this response. (23) _______. Some newer vaccines use genetic instructions to help cells build a harmless protein found on the virus. This method has proven effective in recent outbreaks. (24) _______. For example, mRNA vaccines became widely known during the COVID-19 pandemic. Developing a vaccine involves multiple stages: lab research, animal testing, and human trials. (25) _______. Each phase must follow strict safety protocols and be approved by health authorities. Once approved, vaccines are distributed through public health systems. (26) _______.
(Adapted from National Geographic, “Searching for a Coronavirus Vaccine: How Would It Work?”)
Question 22. A. This immunological response prepares the body to defend against future encounters with actual pathogens
B. These antibody-producing mechanisms enable the immune system to respond more rapidly to subsequent exposures
C. This defensive preparation allows the body to recognize and neutralize genuine threats when they appear
D. These protective protocols help the immune system mount effective responses against real infections