Practice Science TEAS Test

Correct Answer: B

Rationale: The correct answer is B: To contract and expand the lungs. The diaphragm is a dome-shaped muscle that plays a crucial role in respiration by contracting and relaxing to create changes in lung volume, allowing air to flow in and out of the lungs. When the diaphragm contracts, it flattens, increasing the space in the chest cavity and causing inhalation. When it relaxes, it returns to its dome shape, decreasing the space in the chest cavity and causing exhalation. Incorrect choices: A: To regulate air pressure in the lungs - While the diaphragm indirectly affects air pressure by creating changes in lung volume, its primary role is in creating the necessary space for inhalation and exhalation. C: To store oxygen - The diaphragm is a muscle and does not store oxygen. Oxygen is primarily stored in the blood and tissues. D: To break down carbon dioxide - The diaphragm is not involved in breaking down carbon dioxide. Carbon dioxide is

Correct Answer: B

Rationale: The correct answer is B: Glucose. Glucose is a monosaccharide because it is a single sugar molecule, the simplest form of carbohydrates. Starch (A) is a polysaccharide made up of multiple glucose units. Cellulose (C) is also a polysaccharide, not a monosaccharide. Sucrose (D) is a disaccharide composed of glucose and fructose molecules. So, only glucose (B) fits the definition of a monosaccharide in this question.

Correct Answer: B

Rationale: The correct answer is B: Cerebrum. The cerebrum is responsible for voluntary muscle movements as it houses the motor cortex, which controls voluntary movements. The medulla oblongata (A) controls involuntary functions like breathing and heart rate. The hypothalamus (C) regulates body temperature, hunger, and thirst. The thalamus (D) serves as a relay station for sensory information. Therefore, the cerebrum is the correct choice for voluntary muscle movements.

Correct Answer: A

Rationale: The correct answer is A: Kidneys. The kidneys are responsible for filtering waste products, excess fluids, and toxins from the blood to form urine. Step-by-step rationale: 1. The kidneys contain millions of tiny filtering units called nephrons. 2. Blood flows through the nephrons, where waste products are removed and urine is formed. 3. The urine then flows through the ureters to the bladder for storage and eventual elimination. Other choices are incorrect because: B: Pancreas - produces digestive enzymes and regulates blood sugar, not primarily involved in waste filtration. C: Liver - detoxifies chemicals, produces bile, and stores nutrients, but not the primary organ for blood filtration. D: Heart - pumps blood and circulates it throughout the body, not directly involved in waste filtration.

Correct Answer: B

Rationale: The correct answer is B: Melatonin. Melatonin is a hormone produced by the pineal gland that plays a key role in regulating the sleep-wake cycle. It helps control the body's internal clock and signals when it's time to sleep. Cortisol (choice A) is a stress hormone, thyroxine (choice C) regulates metabolism, and insulin (choice D) controls blood sugar levels, but they do not directly regulate the sleep-wake cycle. Melatonin is the only hormone among the choices specifically associated with sleep regulation.