ati teas 7 science

Correct Answer: C

Rationale: The correct answer is C: Small intestine. The small intestine is the primary site for nutrient absorption in the digestive system due to its large surface area, specialized structures called villi, and microvilli that maximize absorption efficiency. Digestive enzymes and bile are also released in the small intestine to break down nutrients for absorption. The other choices are incorrect because the esophagus is responsible for swallowing, the large intestine mainly absorbs water and electrolytes, and the stomach primarily functions in digestion by secreting gastric juices.

Correct Answer: D

Rationale: The main function of the lungs is to exchange oxygen and carbon dioxide between the body and the environment. This process, known as respiration, is essential for cellular function. Step 1: Oxygen is inhaled into the lungs and diffuses into the bloodstream. Step 2: Carbon dioxide produced by cells is carried to the lungs via the bloodstream and exhaled. Choice A is incorrect as the primary function of the lungs is gas exchange, not nutrient transport. Choice B is incorrect as movement coordination is a function of the nervous system. Choice C is incorrect as waste filtration is primarily done by the kidneys and liver.

Correct Answer: C

Rationale: The correct answer is C, the Combined oral contraceptive pill. This method uses hormones like estrogen and progestin to prevent ovulation. Firstly, estrogen suppresses follicle-stimulating hormone (FSH) production, inhibiting follicular development. Secondly, progestin thickens cervical mucus, preventing sperm penetration. Lastly, progestin also inhibits luteinizing hormone (LH) surge, preventing ovulation. Spermicide (A) works by killing sperm but does not prevent ovulation. Barrier methods (B) like condoms and diaphragms physically block sperm from reaching the egg but do not affect ovulation. Intrauterine devices (IUDs) (D) work by preventing sperm from fertilizing the egg or by altering the uterine lining, but they do not directly prevent ovulation.

Correct Answer: C

Rationale: The correct answer is C: Nephron. The nephron is the functional unit of the kidney responsible for filtering blood and reabsorbing essential substances like water, salts, and nutrients back into the body. It consists of various components like the glomerulus, proximal tubule, loop of Henle, and distal tubule, each playing a specific role in the reabsorption process. The renal artery brings blood to the kidney for filtration by the nephron, while the renal vein carries filtered blood away from the kidney. The glomerulus is a part of the nephron responsible for initial filtration of blood. Thus, the nephron is the correct structure for reabsorption, making choices A, B, and D incorrect.

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.