vaccines work by

ATI TEAS 7

TEAS 7 practice test science

1. How do vaccines work?

A. By directly killing pathogens
B. By introducing weakened or inactive versions of pathogens to trigger an immune response
C. By stimulating the immediate production of specific antibodies
D. None of the above

Correct answer: B

Rationale: Vaccines work by introducing weakened or inactive versions of pathogens to trigger an immune response in the body. This exposure helps the immune system recognize and remember the pathogen, enabling a faster and more effective response upon future exposure. Vaccines do not directly kill pathogens but prepare the immune system for a potential encounter, enhancing protection. They also do not stimulate the immediate production of specific antibodies as the immune response takes time to develop upon vaccination. Choice A is incorrect because vaccines do not kill pathogens directly; they prime the immune system to recognize and respond to them. Choice C is incorrect because while vaccines lead to the production of specific antibodies, it is not immediate, as it takes time for the immune response to develop and produce these antibodies.

2. Which gas is the most abundant in Earth's atmosphere?

A. Nitrogen
B. Oxygen
C. Carbon dioxide
D. Argon

Correct answer: A

Rationale: Nitrogen is the most abundant gas in Earth's atmosphere, constituting approximately 78% of the air we breathe. It is essential for various biological processes, including plant growth and nitrogen fixation. Moreover, nitrogen is a key component of the greenhouse effect, playing a crucial role in regulating the planet's temperature. Oxygen, while important for respiration, comprises about 21% of the atmosphere. Carbon dioxide, though vital for photosynthesis and a greenhouse gas, is present in much lower concentrations than nitrogen. Argon, an inert gas, is a minor component of the atmosphere.

3. In the 18th century, women were more likely to die in childbirth compared to the 21st century. What is a possible explanation for why women are less likely to die in childbirth in the present age?

A. Doctors are better equipped to perform cesarean sections.
B. Doctors have more tools to monitor mothers during childbirth, enabling earlier detection of complications.
C. Doctors practice good hand hygiene to prevent the transfer of germs and infections.
D. All of the statements above provide reasonable explanations for the decrease in mortality during childbirth.

Correct answer: D

Rationale: All options are valid explanations for the decrease in maternal mortality during childbirth in modern times. Improved medical knowledge and technology have enabled doctors to perform cesarean sections more effectively, monitor mothers more closely for early detection of complications, and maintain better hygiene practices to reduce the risk of infections. Therefore, all the given statements collectively contribute to the reduction in maternal mortality rates in the 21st century.

4. What are the primary processes involved in breathing?

A. Inspiration and Expiration
B. Inhalation and Exhalation
C. Respiration and Circulation
D. Inspiration and Respiration

Correct answer: A

Rationale: The primary processes involved in breathing are inspiration (inhaling air) and expiration (exhaling air). Inspiration is the process of taking air into the lungs, while expiration is the process of expelling air from the lungs. These two phases are crucial for gas exchange, where oxygen is taken in during inspiration and carbon dioxide is expelled during expiration. Choices B, C, and D are incorrect as they either combine inspiration with respiration or include unrelated processes like respiration and circulation. Therefore, the correct pair of processes involved in breathing is A, inspiration and expiration.

5. Which property of a substance describes its ability to conduct heat or electricity?

A. Reactivity
B. Conductivity
C. Density
D. Viscosity

Correct answer: B

Rationale: Conductivity is the correct property that describes a substance's ability to conduct heat or electricity. Reactivity is related to how readily a substance undergoes chemical reactions, not its ability to conduct heat or electricity. Density refers to the mass per unit volume of a substance, which is different from its ability to conduct heat or electricity. Viscosity measures a substance's resistance to flow, not its ability to conduct heat or electricity.