ATI TEAS 7
ATI TEAS Science Practice Test
1. Which feedback loop inhibits the stimulus or the deviation from homeostasis?
- A. Negative feedback loop
- B. Positive feedback loop
- C. Inhibitory feedback loop
- D. Stimulating feedback loop
Correct answer: A
Rationale: The correct answer is A: Negative feedback loop. Negative feedback loops work to inhibit the stimulus or reduce the deviation from a set point, maintaining homeostasis by counteracting any changes from the norm. In this case, the negative feedback loop acts to minimize any deviation from the body's internal balance, ensuring stability and optimal functioning. Choice B, a positive feedback loop, amplifies the stimulus or deviation, moving systems away from homeostasis. Choice C, an inhibitory feedback loop, is not a commonly recognized term in the context of feedback mechanisms. Choice D, a stimulating feedback loop, is not a standard term and does not accurately describe a feedback loop's role in maintaining homeostasis.
2. During gas exchange in the alveoli, what happens to oxygen?
- A. Oxygen is released from the alveoli into the bloodstream.
- B. Oxygen is absorbed from the alveoli into the bloodstream.
- C. Oxygen is converted into carbon dioxide.
- D. Oxygen is stored in the alveoli for later use.
Correct answer: B
Rationale: During gas exchange in the alveoli, oxygen is absorbed from the alveoli into the bloodstream. This process occurs due to the difference in partial pressures of oxygen between the alveoli and the bloodstream, causing oxygen to move from an area of higher concentration (alveoli) to an area of lower concentration (bloodstream). Oxygen is then transported by red blood cells to tissues throughout the body for cellular respiration. Choice A is incorrect as oxygen moves from the alveoli into the bloodstream, not the other way around. Choice C is incorrect as oxygen is not converted into carbon dioxide during gas exchange. Choice D is incorrect as oxygen is not stored in the alveoli but rather continuously exchanged with carbon dioxide during respiration.
3. What is the difference between the atomic number and the mass number of an atom?
- A. The atomic number is the number of protons in the nucleus, while the mass number is the total number of protons and neutrons in the nucleus.
- B. The atomic number is the number of electrons in an atom, while the mass number is the total number of protons and neutrons in the nucleus.
- C. The atomic number is the number of neutrons in the nucleus, while the mass number is the total number of protons and electrons in an atom.
- D. The atomic number is the number of protons and neutrons in the nucleus, while the mass number is the total number of electrons in an atom.
Correct answer: A
Rationale: The atomic number of an atom represents the number of protons in its nucleus, which defines the element's identity. On the other hand, the mass number corresponds to the total sum of protons and neutrons in the nucleus. Therefore, the key distinction between the atomic number and the mass number lies in the fact that the atomic number specifically counts the protons, whereas the mass number encompasses both protons and neutrons. Choice B is incorrect because the atomic number is not related to the number of electrons but rather to the number of protons. Choice C is incorrect because the atomic number is not the number of neutrons but the number of protons. Choice D is incorrect because the atomic number does not include neutrons; it is solely the number of protons.
4. Why can optical fibers transmit light signals around bends?
- A. Reflection
- B. Refraction
- C. Diffraction
- D. Polarization
Correct answer: B
Rationale: Optical fibers can transmit light signals around bends primarily due to refraction. Refraction is the bending of light as it passes from one medium to another, such as from air to glass in an optical fiber. This bending allows the light signals to travel through the fiber even around bends, making optical fibers an efficient means of transmitting light signals over long distances. Reflection (Choice A) occurs when light bounces off a surface, which is not the primary mechanism allowing light to travel around bends in optical fibers. Diffraction (Choice C) refers to the bending of light waves around obstacles or openings, but it is not the main reason light signals can traverse bends in optical fibers. Polarization (Choice D) is the orientation of light waves in a specific plane, but it does not play a significant role in enabling light to navigate bends in optical fibers.
5. A restaurant employs servers, hosts, and managers in a ratio of 9:2:1. If there are 36 total employees, what is the number of hosts at the restaurant?
- A. 3
- B. 4
- C. 6
- D. 8
Correct answer: C
Rationale: To find the number of hosts in the restaurant, first, express the ratio algebraically as 9x + 2x + 1x = 36, where x represents the common factor. Combine like terms to get 12x = 36. Solve for x by dividing both sides by 12 to get x = 3. To find the number of hosts, multiply the coefficient of hosts (2) by x, which equals 6. Therefore, there are 6 hosts at the restaurant. Choice A, 3, is incorrect as it represents the number of servers. Choices B and D are incorrect as they do not correspond to the number of hosts based on the given ratio.
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