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. Which sentence uses comma splices incorrectly?

A. The baker kneaded the dough, flour dusted her apron, and the oven warmed up.
B. The mountains, shrouded in mist, seemed to disappear into the clouds.
C. He arrived late, having forgotten his keys, and the meeting had already started.
D. The movie, despite its flaws, was surprisingly enjoyable.

Correct answer: C

Rationale: Option (c) incorrectly combines two independent clauses with only a comma. A semicolon or conjunction is needed

3. A baseball is thrown into the air. At the peak of its trajectory, which of the following forces is acting on the ball?

A. Only gravitational force
B. Only the force of air resistance
C. Both gravitational force and the force of air resistance
D. Neither gravitational force nor the force of air resistance

Correct answer: A

Rationale: At the peak, the ball momentarily stops moving upwards. Its inertia keeps it moving horizontally, but there is no force propelling it upwards except for gravity pulling it down.

4. Which phenomenon explains the formation of rainbows in the sky?

A. Diffraction
B. Interference
C. Refraction and dispersion of sunlight by water droplets.
D. Reflection from clouds

Correct answer: C

Rationale: Refraction and dispersion of sunlight by water droplets in the atmosphere separate white light into its constituent colors, creating the rainbow phenomenon.

5. What is the process of converting glucose into ATP, the cell's primary energy currency, called?

A. Cellular respiration
B. Fermentation
C. Photosynthesis
D. Hydrolysis

Correct answer: A

Rationale: Rationale: A) Cellular respiration is the process by which cells convert glucose into ATP, the primary energy currency of the cell. This process involves a series of biochemical reactions that occur in the mitochondria of eukaryotic cells or the cytoplasm of prokaryotic cells. Through cellular respiration, the energy stored in glucose molecules is gradually released and captured in the form of ATP. B) Fermentation is an anaerobic process that occurs in the absence of oxygen. It involves the partial breakdown of glucose to produce ATP and end products such as lactic acid or ethanol. While fermentation can generate ATP, it is less efficient than cellular respiration in terms of energy production. C) Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose. This process occurs in chloroplasts and is the opposite of cellular respiration. While photosynthesis produces glucose,

6. A doctor orders 1 gram of a medication to be administered intravenously. The available vial contains 200 milligrams per milliliter. How many milliliters of the solution should be drawn up?

A. 4 milliliters
B. 5 milliliters
C. 10 milliliters
D. 20 milliliters

Correct answer: B

Rationale: First convert grams to milligrams (1 gram * 1000 milligrams/gram = 1000 milligrams). Then, divide the desired dosage by the concentration per milliliter: 1000 milligrams / 200 milligrams/milliliter = 5 milliliters.