TEAS 7 science practice

Correct Answer: B

Rationale: The correct answer is the Mitral valve. The mitral valve is located between the left atrium and the left ventricle of the heart. Its function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. Choice A, the Tricuspid valve, is incorrect as it is located between the right atrium and right ventricle. Choice C, the Aortic valve, and Choice D, the Pulmonic valve, are also incorrect as they are involved in the circulation of blood leaving the heart rather than preventing backflow within the atria and ventricles.

Correct Answer: B

Rationale: The correct answer is B, Urethra. The urethra is not directly involved in urine production. It is a tube that carries urine from the bladder to the outside of the body. The kidneys are responsible for filtering waste and excess substances from the blood to produce urine. The bladder stores urine until it is expelled from the body. The lungs are not involved in urine production; they are responsible for gas exchange during respiration. Choice A, Kidneys, is directly involved in urine production by filtering the blood to form urine. Choice C, Lungs, plays a role in respiration and oxygen exchange but is not directly involved in urine production. Choice D, Bladder, stores urine before it is excreted from the body and is directly involved in the final stages of urine elimination, unlike the urethra.

Correct Answer: B

Rationale: The correct answer is the kidneys. The kidneys filter blood and remove waste products through the formation of urine. The liver primarily functions in detoxification and metabolism. The spleen is involved in blood filtering and immune function. The pancreas produces digestive enzymes and insulin, not involved in filtering blood.

Correct Answer: C

Rationale: The correct answer is C, urea. Urea is the main nitrogenous waste product eliminated by the kidneys. It is produced in the liver from protein metabolism and excreted in urine. Carbon dioxide is eliminated through the lungs as a waste product of cellular respiration and not by the kidneys. Ammonia, a toxic waste product, is converted to urea in the liver before being excreted by the kidneys. Glucose is a sugar that is reabsorbed by the kidneys and not excreted as waste.

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.