TEAS 7 science practice

Correct Answer: C

Rationale: The main function of the urinary system is to maintain the body's acid-base balance. This is achieved by regulating the levels of electrolytes and water in the body. The kidneys filter waste products from the blood to form urine, which helps to regulate the pH balance. Choice A, transporting oxygen, is primarily the function of the respiratory system. Choice B, fighting off infections, is a function of the immune system. Therefore, the correct answer is maintaining acid-base balance.

Correct Answer: C

Rationale: The main function of the urinary system is to maintain the body's acid-base balance. This is achieved by regulating the levels of electrolytes and water in the body. The kidneys filter waste products from the blood to form urine, which helps to regulate the pH balance. Choice A, transporting oxygen, is primarily the function of the respiratory system. Choice B, fighting off infections, is a function of the immune system. Therefore, the correct answer is maintaining acid-base balance.

Correct Answer: C

Rationale: During a physical change in matter, the original substance undergoes a change in its physical state or appearance without any change in its chemical composition. This means that the original substance can be recovered by physical means, such as melting, freezing, boiling, or condensing. No new substance is formed (option A), the chemical composition remains the same (option B), and energy changes can occur but are not a defining characteristic of a physical change (option D). The ability to recover the original substance by physical means distinguishes physical changes from chemical changes.

Correct Answer: A

Rationale: A) Mouth: The mouth is involved in the mechanical breakdown of food through chewing and the initiation of carbohydrate digestion by the enzyme amylase in saliva, but it does not produce digestive enzymes. The salivary amylase in the mouth helps in breaking down carbohydrates. However, it is not an organ that produces digestive enzymes. B) Stomach: The stomach produces gastric juices containing enzymes like pepsin that help break down proteins. C) Pancreas: The pancreas produces various digestive enzymes such as amylase, lipase, and proteases that aid in the digestion of carbohydrates, fats, and proteins. D) Small intestine: The small intestine produces enzymes such as peptidases, sucrase, lactase, and maltase that further break down proteins, carbohydrates, and fats for absorption. Therefore, the mouth is the organ that is NOT involved in the production of digestive enzymes.

Correct Answer: C

Rationale: The involuntary reflex arc that withdraws your hand from a hot object involves both the central nervous system (CNS) and the peripheral nervous system (PNS). When your hand touches a hot object, sensory neurons in the PNS detect the heat and send signals to the spinal cord in the CNS. The spinal cord processes this information and sends a signal back through motor neurons in the PNS to move your hand away from the hot object. This coordinated response requires the collaboration of both the CNS and PNS to protect the body from harm. Choice A is incorrect because the reflex arc involves more than just the central nervous system. Choice B is incorrect because the reflex arc involves more than just the peripheral nervous system. Choice D is incorrect because the reflex arc also involves motor neurons, not just sensory neurons.