Science TEAS Practice Test

Correct Answer: A

Rationale: The correct answer is A: The sinoatrial node. The SA node is known as the heart's natural pacemaker as it initiates electrical impulses that regulate the heart rate. It is located in the right atrium and generates rhythmic electrical signals that stimulate the cardiac muscle to contract. The left ventricle (B), aorta (C), and tricuspid valve (D) do not serve as electrical stimulators of the cardiac muscle. The left ventricle is a chamber that pumps oxygenated blood, the aorta is the largest artery that carries blood away from the heart, and the tricuspid valve controls blood flow between the right atrium and right ventricle.

Correct Answer: A

Rationale: The correct answer is A: Tachycardia. Tachycardia is a condition where the heart rate is abnormally fast, typically above 100 bpm. In this case, with a heart rate of 118 bpm, it falls under tachycardia. Explanation: 1. Tachycardia refers to an elevated heart rate, which is present in this scenario. 2. Apnea is the absence of breathing, not related to heart rate. 3. Bradycardia is a condition where the heart rate is too slow, typically below 60 bpm. 4. Tachypnea is rapid breathing, not related to heart rate. In summary, tachycardia is the correct term for a heart rate of 118 bpm, making the other options incorrect due to their associations with different physiological functions.

Correct Answer: D

Rationale: Density is considered an intensive property because it remains constant regardless of the amount of the substance present. Intensive properties do not depend on the quantity of the material. Density is defined as mass per unit volume, so it is independent of the amount of the substance. On the other hand, mass and volume (choices A and C) are extensive properties that change with the amount of the substance, making them not intensive. Weight (choice B) is also not an intensive property as it depends on the gravitational force acting on the object, which can vary.

Correct Answer: B

Rationale: The correct answer is B: Liver. The liver is primarily responsible for detoxification in the body as it processes and removes toxins, drugs, and other harmful substances from the bloodstream. It metabolizes these toxins into less harmful compounds that can be excreted from the body. The kidney, although important for filtering waste and regulating electrolytes, is not primarily responsible for detoxification. The lung primarily functions in gas exchange, and the heart is responsible for pumping blood throughout the body, not for detoxification. Therefore, the liver is the correct choice for the organ primarily responsible for detoxification.

Correct Answer: A

Rationale: The correct answer is A: Phenotype. Phenotype refers to the physical and visible expression of a genetic trait. It includes observable characteristics like eye color, height, and hair texture. This is different from genotype, which represents the genetic makeup of an organism. Allele refers to different forms of a gene, and gamete is a reproductive cell. Thus, in this context, phenotype best describes the physical manifestation of a genetic trait, making it the correct answer.