1. Which part of the heart generates the QRS complex on an ECG?

A. Sinoatrial node (SA node)
B. Atrioventricular node (AV node)
C. Bundle of His
D. Ventricular muscle cells

Correct answer: D

Rationale: The correct answer is D, ventricular muscle cells. The QRS complex on an ECG represents the depolarization of the ventricles. This electrical activity is generated by the spread of impulses through the bundle branches and Purkinje fibers to the ventricular muscle cells. The SA node (option A) is responsible for initiating the electrical impulse in the heart, but it does not directly generate the QRS complex. The AV node (option B) delays the impulse to allow for proper coordination of atrial and ventricular contractions. The Bundle of His (option C) and its branches facilitate the conduction of the electrical signal from the AV node to the ventricles but do not generate the QRS complex directly.

2. Which of the following is a common property of both acids and bases?

A. React with metals to produce hydrogen gas
B. Taste sour
C. Turn blue litmus paper red
D. Conduct electricity when dissolved in water

Correct answer: d

Rationale: Both acids and bases conduct electricity when dissolved in water. The other choices are specific to either acids or bases.

3. What is the half-life of a radioactive isotope, and how does it relate to its decay rate?

A. The time it takes for half of the initial sample to decay.
B. The time it takes for all the sample to decay.
C. The rate at which new isotopes are created.
D. The energy released during decay.

Correct answer: A

Rationale: Half-life tells the time it takes for half of the original radioactive nuclei to decay, offering an indication of the decay rate.

4. Which additional information would be MOST helpful in further understanding the issue of microplastics?

A. The economic costs associated with plastic pollution cleanup.
B. The specific types of microbes used in bioremediation processes.
C. The historical timeline of plastic production and its global distribution.
D. The aesthetic impact of plastic pollution on beaches and tourism.

Correct answer: B

Rationale: Understanding the specific microbes used in bioremediation would directly contribute to knowledge about the solution proposed in the passage.

5. Which phrase best describes the tone of the following sentence: "He slammed his fist on the table, his voice booming with anger."

A. Playful
B. Formal
C. Agitated
D. Melancholy

Correct answer: C

Rationale: The verbs and descriptive language convey strong emotions and agitation.

6. The lymphatic system is primarily responsible for:

A. Transporting nutrients throughout the body
B. Removing excess fluids and waste products from tissues
C. Producing red blood cells
D. Regulating body temperature

Correct answer: B

Rationale: The correct answer is B: 'Removing excess fluids and waste products from tissues.' The lymphatic system plays a crucial role in maintaining fluid balance in the body by collecting excess interstitial fluid and returning it to the bloodstream. This system also helps in removing waste products, pathogens, and toxins from tissues, contributing to the body's immune response. Options A, C, and D are incorrect because transporting nutrients, producing red blood cells, and regulating body temperature are primarily the functions of other systems in the body such as the circulatory system, bone marrow, and the thermoregulatory system, respectively.