Practice Science TEAS Test

Correct Answer: A

Rationale: The correct answer is A: Arteries. Arteries carry blood away from the heart because they have thick, muscular walls that can withstand the high pressure of blood being pumped by the heart. Arterioles are smaller branches of arteries, not the main vessels carrying blood away from the heart. Veins carry blood back to the heart, while venules are small vessels that collect blood from capillaries. Thus, the correct choice is arteries as they are specifically designed to carry blood away from the heart with their unique structure and function.

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.

Correct Answer: A

Rationale: The correct answer is A: Abdominal. The peritoneum primarily lines the abdominal cavity, providing a protective and lubricating membrane for the abdominal organs. The peritoneum does not line the dorsal (B), ventral (C), or thoracic (D) cavities. The dorsal cavity is lined by the meninges, the ventral cavity is lined by serous membranes, and the thoracic cavity is lined by the pleura. Therefore, the peritoneum specifically lines the abdominal cavity, making choice A the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Adhesion. Water is considered a universal solvent because of its strong ability to adhere to other substances and dissolve a wide range of solutes. This property is essential for water to dissolve various molecules and ions, making it an effective solvent in nature. Cohesion (A) refers to water molecules sticking to each other, not to other substances. Molarity (C) is a measure of concentration, not a property of water as a solvent. Dilution (D) refers to the process of reducing the concentration of a solute in a solution, not the reason why water is a universal solvent.

Correct Answer: A

Rationale: The correct answer is A: Bicarbonate. CO2 is primarily transported in the blood as bicarbonate ions. This process involves carbonic anhydrase converting CO2 into carbonic acid, which then dissociates into bicarbonate and hydrogen ions. Bicarbonate is the main form in which CO2 is transported from tissues to the lungs for elimination. Choice B, carbamino compounds, refers to CO2 bound to amino groups in hemoglobin, but this method is a minor mode of CO2 transport. Choice C, None of these, is incorrect as bicarbonate is indeed the primary mode of CO2 transport. Choice D, Plasma, is incorrect as CO2 is not directly transported in the blood as plasma but rather in the form of bicarbonate ions.