ati teas 7 science

Correct Answer: C

Rationale: The correct answer is C: Buffering system. The body maintains a relatively constant blood pH level through the buffering system, which involves the action of bicarbonate ions, carbonic acid, and other buffering molecules that help regulate pH by neutralizing excess acids or bases. This system acts quickly to prevent drastic changes in blood pH when there are fluctuations in blood carbon dioxide concentration. Cellular respiration (A) generates carbon dioxide, gas exchange (B) involves the exchange of gases in the lungs, and deoxygenation (D) refers to the loss of oxygen by the blood, but these processes are not primarily responsible for maintaining blood pH stability.

Correct Answer: D

Rationale: The correct answer is D, the medium's properties. The speed of a wave in a given medium is determined by the properties of that medium, such as its density and elasticity. This affects how fast the wave can travel through the medium. Amplitude (A) is the height of a wave, which does not directly impact the speed of the wave. Wavelength (B) is the distance between two consecutive points of a wave, and while it can affect the wave's behavior, it does not solely determine its speed. Frequency (C) is the number of wave cycles that pass a point in a given time, which is related to speed but not the sole determinant. Therefore, the correct answer is D as the properties of the medium directly influence the speed of the wave.

Correct Answer: B

Rationale: The correct answer is B: Bronchitis. Bronchitis is the inflammation of the bronchi, leading to symptoms like cough and mucus production. Pneumonia (A) is an infection in the lungs, not specifically inflammation of the bronchi. Emphysema (C) is a chronic lung condition characterized by damaged air sacs in the lungs, not bronchial inflammation. Pleurisy (D) is inflammation of the lining of the lungs, not the bronchi. Therefore, based on the symptoms described, bronchitis is the most suitable term for inflammation of the bronchi.

Correct Answer: A

Rationale: The P wave on an ECG represents atrial depolarization. During the cardiac cycle, the electrical impulse originates in the sinoatrial (SA) node, causing the atria to contract. This depolarization of the atria is reflected as the P wave on the ECG. This occurs before the ventricles depolarize (choice B), repolarize (choice D), or before the atria repolarize (choice C). Therefore, the correct answer is A because the P wave specifically represents atrial depolarization in the cardiac cycle.

Correct Answer: A

Rationale: The correct answer is A: Stapes. The stapes is the smallest bone in the human body, located in the middle ear. It plays a crucial role in transmitting sound vibrations to the inner ear. The other choices are incorrect because the patella is a knee bone, phalanges are finger bones, and ribs are chest bones, none of which are the smallest bone in the body. The stapes' small size and specific location make it uniquely suited for its function in hearing.