Practice TEAS Science Test

Correct Answer: B

Rationale: The correct answer is B: Depolarization of the SA node. The P-wave in an ECG represents atrial depolarization, which is initiated by the SA node. This electrical signal spreads through the atria causing them to contract. Choice A is incorrect because the P-wave corresponds to atrial depolarization, not repolarization. Choice C is incorrect as the QRS complex represents ventricular depolarization. Choice D is incorrect as the T-wave represents ventricular repolarization. Therefore, the SA node depolarization is accurately represented by the P-wave in an ECG.

Correct Answer: B

Rationale: The correct answer is B: Hip. A ball-and-socket joint allows for a wide range of motion in multiple directions. The hip joint fits this description, with the rounded head of the femur fitting into the socket of the pelvis. This joint enables movements like flexion, extension, abduction, adduction, and rotation. The other choices, such as the knee (A), elbow (C), and wrist (D), are not ball-and-socket joints. The knee is a hinge joint, the elbow is a hinge joint as well, and the wrist is a condyloid joint.

Correct Answer: B

Rationale: The primary function of white blood cells is to fight infection. They are key components of the immune system, identifying and attacking pathogens like bacteria and viruses. White blood cells produce antibodies to neutralize invaders. This function helps the body defend against illnesses and maintain overall health. Choices A, C, and D are incorrect because carrying oxygen (A) is primarily done by red blood cells, transporting nutrients (C) is mainly performed by blood plasma, and transporting waste (D) is mainly the role of the kidneys and liver.

Correct Answer: D

Rationale: The correct answer is D because a positive correlation indicates that as one variable increases, the other variable also increases. In this case, when plotting rainfall against plant length, if the line trends to the upper right, it shows that as rainfall increases, the plant length also increases. This demonstrates a positive correlation. A is incorrect because it describes a negative correlation where an increase in rainfall leads to a decrease in plant stem length. B is incorrect as it suggests a positive correlation between rainfall and roots length. C is incorrect as a line trending to the lower right also indicates a negative correlation between the variables.

Correct Answer: A

Rationale: The correct answer is A: Mediastinum. The mediastinum is the space between the lungs that contains vital structures such as the heart, major blood vessels, esophagus, and trachea. It separates the lungs into right and left compartments. The pericardial cavity (B) is the space that surrounds the heart within the mediastinum. The pleural cavity (C) is the space between the lungs and the chest wall, not between the lungs themselves. Thoracic space (D) is a vague term and does not specifically refer to the space between the lungs.