ATI TEAS Practice Science Test

Correct Answer: B

Rationale: The correct answer is B: Ribcage. The ribcage is a bony structure that surrounds and protects the lungs. It consists of ribs, sternum, and thoracic vertebrae, forming a protective cage around the vital organs in the thoracic cavity. The ribs provide a barrier against external forces and help maintain the shape and integrity of the lungs. The other choices are incorrect because the femur is a bone in the leg, the scapula is a bone in the shoulder, and the skull protects the brain, not the lungs.

Correct Answer: C

Rationale: The correct answer is C: Flexor. Flexor muscles are responsible for bending a joint by decreasing the angle between the bones they act upon. They contract to bring two body parts closer together. Cardiac muscles (A) are found in the heart and control its pumping action. Extension (B) refers to the straightening of a joint, not bending. Smooth muscles (D) are found in various organs and are not directly involved in joint movement. Therefore, the flexor muscle (C) is the correct choice for causing a joint to bend.

Correct Answer: B

Rationale: The correct answer is B because urine is formed in the kidney during the process of fluid filling the collecting duct. This is where the final concentration and composition of urine are regulated. Before reaching the collecting duct, the initial filtration of blood occurs in the glomerulus (eliminating options C) and the fluid does not become urine until it has passed through the collecting duct (eliminating options A and D). So, the correct sequence is filtration in the glomerulus, reabsorption and secretion in the tubules, and final urine formation in the collecting duct.

Correct Answer: D

Rationale: The correct answer is D because killer T cells have receptors that can recognize specific proteins displayed on the surface of infected cells. This recognition is crucial for the immune system to target and destroy infected cells effectively. The other choices are incorrect because B cells do not flag infected cells with amino acids (A), viral RNA remnants are not used for recognition by killer T cells (B), and macrophages do not directly help in identifying infected cells for killer T cell response (C). Overall, choice D stands out as the most accurate explanation based on the mechanism of T cell recognition in the immune response.

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.