1. What is the process by which the body maintains a relatively constant blood pH level, even with changes in blood carbon dioxide concentration?

A. Cellular respiration
B. Gas exchange
C. Buffering system
D. Deoxygenation

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 consists of chemical substances that can absorb excess hydrogen ions or release hydrogen ions to adjust pH levels. This system helps prevent drastic changes in blood pH even when there are fluctuations in blood carbon dioxide concentration. Cellular respiration and gas exchange are processes related to obtaining and utilizing oxygen, while deoxygenation refers to the removal of oxygen from a substance. Therefore, the buffering system is specifically responsible for regulating blood pH levels in response to changes in carbon dioxide concentration.

2. The sentence "The audience was captivated by the speaker's compelling story" implies that the audience:

A. Was bored and disinterested.
B. Found the story confusing.
C. Was completely absorbed and engaged.
D. Disagreed with the speaker's message.

Correct answer: C

Rationale: "Captivated" suggests the audience was completely held by the speaker's story.

3. The phrase "survival of the fittest" refers to:

A. Organisms with the most complex anatomical structures are more likely to survive and reproduce.
B. Organisms that demonstrate the best adaptations to their environment have a higher chance of survival and reproduction.
C. All organisms have an equal probability of survival and reproductive success regardless of their traits.
D. Only the strongest and most aggressive individuals within a population will survive and reproduce.

Correct answer: B

Rationale: Rationale: The phrase "survival of the fittest" is often associated with the concept of natural selection, which was proposed by Charles Darwin. Natural selection is the process by which organisms that are best adapted to their environment are more likely to survive and reproduce, passing on their advantageous traits to the next generation. This process does not necessarily favor the most complex anatomical structures (option A) or the strongest and most aggressive individuals (option D). Instead, it emphasizes the importance of adaptations that enhance an organism's ability to survive and reproduce in a specific environment. Option C is incorrect because natural selection results in differential reproductive success based on an organism's traits, meaning that not all organisms have an equal probability of survival and reproductive success.

4. What is the term for a solution that has exactly the same concentration of solute as another solution?

A. Saturated solution
B. Unsaturated solution
C. Isotonic solution
D. Concentrated solution

Correct answer: c

Rationale: An isotonic solution has the same concentration of solute as another solution. The other choices do not accurately describe an isotonic solution.

5. Newton's rings are a visual demonstration of:

A. Diffraction
B. Doppler effect
C. Polarization
D. Thin-film interference

Correct answer: D

Rationale: Newton's rings are a series of concentric colored rings observed when light is reflected between a spherical surface and a flat surface. This phenomenon is a result of thin-film interference, which occurs due to the varying thickness of the air gap between the surfaces. The interference of light waves results in constructive and destructive interference, leading to the formation of the rings. Diffraction, the bending of light around obstacles, is not the cause of Newton's rings. The Doppler effect involves the change in frequency of waves due to motion and is not relevant in this context. Polarization refers to the orientation of electromagnetic waves, which is not the primary factor in the formation of Newton's rings. Therefore, the correct answer is D: Thin-film interference.

6. Half-life refers to the characteristic time it takes for:

A. Radioactive intensity to completely disappear
B. The number of neutrons in a nucleus to double
C. The number of protons in a nucleus to change
D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: The correct answer is D: An isotope to decay by half of its initial quantity. The half-life of a substance is the time it takes for half of the initial quantity of radioactive atoms to decay. This is a characteristic property of each radioactive isotope and is used to determine the rate of decay of a substance. Option A is incorrect because radioactive intensity does not completely disappear in half-life, it only decreases by half. Options B and C are unrelated to the concept of half-life and do not accurately describe its definition.