ati teas 7 science

Correct Answer: A

Rationale: The correct answer is A: Atom. An atom is the smallest unit of an element that retains its chemical properties. Atoms are composed of protons, neutrons, and electrons. Molecules (B) are made up of two or more atoms bonded together. Compounds (C) are substances composed of two or more different elements chemically bonded. Mixtures (D) are combinations of two or more substances that are physically mixed but not chemically bonded. Therefore, in this context, the correct answer is atom as it specifically refers to the smallest amount of an element that can exist independently with its unique chemical properties.

Correct Answer: A

Rationale: The correct answer is A: Penicillins. Penicillins target the cell wall of bacteria by inhibiting the synthesis of peptidoglycan, a crucial component of the bacterial cell wall. This disrupts the integrity of the cell wall, leading to bacterial cell lysis. Tetracyclines (B), Macrolides (C), and Fluoroquinolones (D) target different bacterial components like protein synthesis or DNA replication, making them incorrect choices for this question.

Correct Answer: B

Rationale: The correct answer is B: Ball-and-socket joint. This joint allows for the greatest range of motion due to its structure, where a rounded bone fits into a cup-like socket, enabling movement in multiple directions. This design permits flexion, extension, abduction, adduction, and rotation, providing a wide range of motion compared to other joint types. A: Hinge joints allow movement in one plane (like the elbow or knee). C: Pivot joints allow rotation around a central axis (like the neck). D: Saddle joints have more limited motion (like the thumb).

Correct Answer: B

Rationale: The correct answer is B: Pulmonary artery. The pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation. This is a crucial step in the pulmonary circulation system. The pulmonary vein carries oxygenated blood from the lungs back to the heart, so it does not transport blood from the heart to the lungs. The aorta is responsible for carrying oxygenated blood from the heart to the rest of the body, not to the lungs. The superior vena cava is a large vein that carries deoxygenated blood from the upper body to the heart, not to the lungs. Therefore, the pulmonary artery is the correct choice for transporting blood from the heart to the lungs.

Correct Answer: C

Rationale: The correct answer is C: Vitamin K. Vitamin K is essential for blood clotting as it helps in the synthesis of clotting factors. Without adequate vitamin K, the blood cannot clot properly, leading to excessive bleeding. Vitamin A (Choice A) is crucial for vision and immune function, not blood clotting. Vitamin C (Choice B) is important for collagen synthesis and immune function, not blood clotting. Vitamin D (Choice D) is essential for bone health and immune function, not blood clotting. Thus, the correct choice is Vitamin K as it plays a direct role in the blood clotting process.