ATI TEAS Practice Science Test

Correct Answer: D

Rationale: The correct answer is D because it specifically refers to the process of selective permeability by stating that sodium ions must travel through ion channels to enter the cell. This demonstrates that the cell membrane allows certain substances to pass through while blocking others. Receptors on the cell's surface (A) and cell communication (B) are related to cell function but do not directly confirm selective permeability. Environmental changes affecting cell size (C) are more about cell response than membrane permeability. In summary, choice D is correct because it directly addresses the concept of selective permeability, while the other choices do not provide direct evidence of this property.

Correct Answer: C

Rationale: The correct answer is C: Hypothalamus. The hypothalamus is a major structure of the limbic system responsible for regulating various essential functions like emotions, behavior, and physiological processes. It plays a crucial role in the control of thirst, hunger, body temperature, and hormonal regulation. The brainstem (A) is involved in basic life functions like breathing and heart rate, but it is not a part of the limbic system. The spinal cord (B) primarily functions in transmitting sensory and motor signals but is not directly related to the limbic system. The cerebral cortex (D) is responsible for higher-order thinking, sensory processing, and motor functions but is not a major structure of the limbic system.

Correct Answer: B

Rationale: The correct answer is B: Liver. The liver plays a crucial role in storing and metabolizing vitamins, releasing them as needed when intake decreases. It helps maintain vitamin levels in the body. The other choices are incorrect because the appendix has no role in vitamin absorption or regulation, the pancreas primarily aids in digestion and hormone regulation, and the stomach's main function is to break down food, not regulate vitamin levels.

Correct Answer: C

Rationale: The correct order of airflow in the lungs is Trachea, Bronchi, Bronchioles, Alveoli (Option C). The rationale is: 1. Air enters through the trachea. 2. Trachea branches into bronchi. 3. Bronchi further divide into bronchioles. 4. Bronchioles lead to the alveoli where gas exchange occurs. Summary: Option A is incorrect as it starts with bronchi before the trachea. Option B is incorrect as it reverses the order of bronchioles and bronchi. Option D is incorrect as it places alveoli before bronchioles and trachea before bronchi.

Correct Answer: A

Rationale: The correct answer is A: Diffusion. Gas exchange in the respiratory system occurs through diffusion, where oxygen moves from the alveoli in the lungs to the blood and carbon dioxide moves from the blood to the alveoli. This process is driven by a concentration gradient, allowing for the exchange of gases between the air and blood. Exhalation (choice B) is the process of expelling air from the lungs, not the mechanism of gas exchange. Inspiration (choice C) is the process of inhaling air into the lungs, but it is not directly involved in gas exchange. Ventilation (choice D) refers to the movement of air into and out of the lungs and is necessary for gas exchange to occur but is not the actual mechanism of gas exchange itself.