1. What is the difference between a sensory neuron and a motor neuron?

A. Sensory neurons carry signals away from the brain, while motor neurons carry signals towards the brain.
B. Sensory neurons control voluntary muscles, while motor neurons control involuntary muscles.
C. Sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system.
D. Sensory neurons detect light, while motor neurons detect sound.

Correct answer: A

Rationale: The correct answer is A because sensory neurons are responsible for carrying signals from sensory receptors towards the central nervous system (brain and spinal cord), allowing us to perceive sensations such as touch, taste, smell, sight, and sound. On the other hand, motor neurons carry signals from the central nervous system to muscles and glands, enabling movement and responses. Therefore, sensory neurons carry signals away from the brain, while motor neurons carry signals towards the brain, making option A the most accurate choice among the options provided.

2. 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.'

3. What is the difference between DNA and RNA?

A. Both are double-stranded.
B. DNA contains deoxyribose sugar, while RNA contains ribose sugar.
C. RNA contains the nitrogenous base uracil, while DNA contains thymine.
D. Both are identical molecules.

Correct answer: B

Rationale: Rationale: A) Incorrect. DNA is double-stranded, but RNA is typically single-stranded. B) Correct. DNA contains deoxyribose sugar, which lacks an oxygen atom on the 2' carbon of the sugar ring, while RNA contains ribose sugar, which has an additional hydroxyl group on the 2' carbon. C) Incorrect. RNA contains the nitrogenous base uracil, while DNA contains thymine. D) Incorrect. DNA and RNA have distinct structures and functions, so they are not identical molecules.

4. Which of the following best describes a chemical change?

A. Melting ice to form water
B. Dissolving sugar in water
C. Burning wood to produce ash
D. Crushing a can to reduce its size

Correct answer: c

Rationale: Chemical changes involve the formation of new substances with different chemical properties. Burning wood involves a chemical reaction where wood undergoes combustion, breaking down its chemical structure to produce new substances like ash and gases.

5. What transport mechanism uses vesicles to move materials within the cell?

A. Endocytosis
B. Active transport
C. Diffusion
D. Exocytosis

Correct answer: A

Rationale: The correct answer is A: Endocytosis. Endocytosis is a transport mechanism in which cells take in molecules or particles by engulfing them in a vesicle. This process allows materials to be transported within the cell. Active transport (option B) requires energy to move molecules across the cell membrane against their concentration gradient. Diffusion (option C) is the movement of molecules from an area of high concentration to an area of low concentration. Exocytosis (option D) is the process by which cells release substances from vesicles into the extracellular environment. Therefore, endocytosis is the transport mechanism that uses vesicles to move materials within the cell.

6. She decides to illustrate the organizational structure. Which of the following elements is

A. Level of authority
B. Lines of communication
C. Span of control
D. Unity of direction

Correct answer: D

Rationale: The correct answer is D, 'Unity of direction.' In the context of illustrating organizational structure, unity of direction refers to the concept that activities within an organization should be directed towards a common goal. It ensures that all efforts are aligned and coordinated towards achieving the organization's objectives. This element helps in avoiding conflicts and confusion by providing clarity and focus on the overall mission of the organization, which is essential for effective organizational performance. Level of authority, lines of communication, and span of control are important elements in organizational structure as well, but in this scenario, unity of direction specifically pertains to the coordination and alignment of activities towards a common purpose.