1. Action potentials, the all-or-nothing electrical signals traveling along neurons, are generated by the movement of:

A. Glucose
B. Sodium and potassium ions
C. Neurotransmitters
D. Myelin

Correct answer: B

Rationale: The correct answer is B: Sodium and potassium ions. Action potentials are generated by the movement of sodium and potassium ions across the neuronal membrane. During depolarization, sodium ions rush into the cell, causing a change in electrical charge. This influx of positive ions triggers the opening of voltage-gated potassium channels, allowing potassium ions to exit the cell during repolarization. Glucose is a source of energy for cells but does not directly generate action potentials. Neurotransmitters are chemical messengers released at synapses, while myelin is a fatty substance that insulates axons, speeding up the conduction of action potentials but not directly generating them.

2. Define "friction" in terms of opposing motion.

A. A force that increases motion
B. A force that accelerates motion
C. A force that opposes motion
D. A force that creates motion

Correct answer: c

Rationale: Friction acts opposite to the direction of motion, resisting or slowing down the movement of objects.

3. Which muscle plays a significant role in the process of forced exhalation by contracting to reduce the thoracic cavity volume?

A. Diaphragm
B. External intercostal muscles
C. Internal intercostal muscles
D. Abdominal muscles

Correct answer: C

Rationale: The correct answer is C: Internal intercostal muscles. During forced exhalation, these muscles contract to depress the ribs and decrease the thoracic cavity volume, assisting in pushing air out of the lungs. The diaphragm is primarily responsible for inhalation by contracting to increase thoracic cavity volume. External intercostal muscles aid in inhalation by elevating the ribs. Abdominal muscles are involved in activities like coughing, sneezing, and forced exhalation by compressing the abdominal contents to further reduce thoracic volume. Therefore, the internal intercostal muscles have a significant role in forced exhalation.

4. In which direction do the particles of the medium move in a transverse wave?

A. Perpendicular to the direction of wave travel
B. Parallel to the direction of wave travel
C. In a circular motion
D. Opposite to the direction of wave travel

Correct answer: a

Rationale: In a transverse wave, particle displacement occurs perpendicular to the direction of wave travel.

5. The primary function of the strong nuclear force is:

A. Binding electrons in atomic orbitals
B. Binding protons and neutrons within the nucleus
C. Mediating the attractive force between opposite charges
D. Mediating the repulsive force between like charges

Correct answer: B

Rationale: The strong nuclear force is responsible for binding protons and neutrons within the nucleus. This force is crucial for overcoming the electrostatic repulsion between positively charged protons in the nucleus, holding the nucleus together. Option A is incorrect as it refers to the role of the electromagnetic force in binding electrons in atomic orbitals. Option C describes the electromagnetic force that mediates the attraction between opposite charges, while option D refers to the electromagnetic force mediating the repulsion between like charges. Understanding the primary function of the strong nuclear force helps explain the stability and structure of atomic nuclei.

6. The small intestine is where most of the chemical digestion and nutrient absorption occur. What is the finger-like projection in the small intestine that increases its surface area for absorption?

A. Rugae
B. Villi
C. Microvilli
D. All of the above

Correct answer: D

Rationale: The correct answer is D, 'All of the above.' The finger-like projection in the small intestine that increases its surface area for absorption is primarily the villi and microvilli. Villi are small, finger-like projections that line the inner wall of the small intestine, while microvilli are even smaller projections on the surface of the villi. Both structures significantly increase the surface area of the small intestine, allowing for more efficient absorption of nutrients. Rugae, on the other hand, are folds in the stomach lining that help with expansion when the stomach is full. Therefore, the rugae are not directly related to the increased surface area for absorption in the small intestine, making options A and B incorrect choices. Overall, options A, B, and C are all related to the structure of the small intestine but serve different functions, so the most appropriate answer is D, 'All of the above.'