Practice TEAS Science Test

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.

Correct Answer: C

Rationale: The correct answer is C: Graduated cylinder. To measure the volume of a solid accurately, we need to use a container with volume markings like a graduated cylinder. Step 1: Fill the graduated cylinder with a known amount of water. Step 2: Drop the solid into the water and measure the new water level. Step 3: Subtract the initial water level from the final level to find the volume displaced, which is the volume of the solid. The other choices are incorrect because a triple beam balance measures mass, a measuring wheel is for linear measurements, and using a measuring wheel and formula may not provide accurate volume measurements.

Correct Answer: D

Rationale: The correct answer is D: Sympathetic nervous system. This system is responsible for activating the 'fight or flight' response in situations of stress or danger. It triggers physiological changes such as increased heart rate, dilation of pupils, and release of adrenaline. The central nervous system (A) includes the brain and spinal cord but doesn't directly control this response. The peripheral nervous system (B) includes nerves outside the brain and spinal cord but doesn't specifically regulate 'fight or flight'. The autonomic nervous system (C) includes both sympathetic and parasympathetic divisions, with the sympathetic division being the one involved in the 'fight or flight' response.

Correct Answer: B

Rationale: The correct answer is B: Medulla oblongata. The medulla oblongata, located in the brainstem, controls essential functions like breathing and heart rate. It contains centers that regulate these automatic processes. The cerebrum (A) is responsible for higher brain functions, not controlling basic physiological functions. The thalamus (C) serves as a relay station for sensory information, not for regulating breathing and heart rate. The cerebellum (D) plays a role in coordination and movement, not in controlling vital functions like breathing and heart rate.

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.