1. During a healthy heartbeat, the P wave on an ECG represents

A. The repolarization of the ventricles.
B. The electrical conduction through the AV node.
C. The contraction phase of the ventricles (systole)
D. The depolarization of the atria.

Correct answer: D

Rationale: The correct answer is D: The P wave on an ECG represents the depolarization of the atria. During a healthy heartbeat, the P wave is the first positive deflection seen on the ECG and reflects the initiation of the electrical impulse in the atria, leading to atrial contraction. It is followed by the QRS complex, which represents the depolarization of the ventricles. Options A, B, and C are incorrect because the P wave specifically corresponds to atrial depolarization, not repolarization of the ventricles, electrical conduction through the AV node, or ventricular contraction. Understanding the sequence of electrical events in the heart as represented on an ECG is crucial for interpreting cardiac function and identifying potential abnormalities.

2. Pinpoint the smallest bone in the human body.

A. Stapes (Middle ear bone)
B. Patella (Kneecap)
C. Phalanges (Finger bones)
D. Ribs

Correct answer: A

Rationale: The stapes, crucial for hearing, transmits and amplifies sound vibrations. Despite its size, it plays a vital role in auditory perception.

3. A pizza has a diameter of 40cm. What is its perimeter (circumference)?

A. 62.8cm
B. 125.5cm
C. 125.6cm
D. 251.2cm

Correct answer: C

Rationale: Multiply the diameter by Ï€: perimeter = Ï€ * diameter = Ï€ * 40cm â‰ˆ 125.6cm (Note: Ï€ â‰ˆ 3.14)

4. The gradual change in a species over time in response to environmental pressures is best described by:

A. Punctuated equilibrium (rapid bursts of evolution)
B. Gradualism (slow and continuous change)
C. Founder effect (genetic drift in a small population)
D. Adaptive radiation (rapid diversification of a species)

Correct answer: B

Rationale: Rationale: A) Punctuated equilibrium refers to rapid bursts of evolution followed by long periods of stability, rather than gradual change over time in response to environmental pressures. B) Gradualism is the process by which species evolve through slow and continuous changes over time in response to environmental pressures. This gradual change can lead to the development of new traits and adaptations. C) Founder effect is a type of genetic drift that occurs when a small group of individuals establishes a new population, leading to a loss of genetic variation compared to the original population. It does not specifically describe the gradual change in a species over time. D) Adaptive radiation is the rapid diversification of a species into a variety of forms to exploit different ecological niches, but it does not specifically refer to the gradual change in response to environmental pressures. Therefore, the best description of the gradual change in a species over time in response to e

5. Which vitamin plays a crucial role in calcium absorption in the small intestine?

A. Vitamin A
B. Vitamin C
C. Vitamin D
D. Vitamin E

Correct answer: C

Rationale: The correct answer is C: Vitamin D. Vitamin D plays a crucial role in calcium absorption in the small intestine because it helps regulate the levels of calcium and phosphorus in the body. When vitamin D is present, it stimulates the production of proteins that facilitate the absorption of calcium from the intestine into the bloodstream. Without adequate levels of vitamin D, the body struggles to absorb calcium efficiently, which can lead to weakened bones and other health issues. While vitamins A, C, and E are important for various functions in the body, they do not directly impact calcium absorption in the same way that vitamin D does.

6. What is the function of ribosomes?

A. Packaging and transporting proteins
B. Storing genetic material
C. Controlling cell division
D. Synthesizing proteins

Correct answer: D

Rationale: The correct answer is D: 'Synthesizing proteins.' Ribosomes are the cellular organelles responsible for protein synthesis. They read the mRNA and assemble amino acids into proteins according to the genetic information encoded in the mRNA. This process is crucial for building and maintaining cellular structures, enzymes, and various other proteins essential for the functioning of the cell. Options A, B, and C do not accurately describe the primary function of ribosomes, making them incorrect choices for this question.