Nursing Elites

1. What is the difference between a pure substance and a mixture?

• A. Pure substances have fixed composition, mixtures don't.
• B. Mixtures have fixed composition, pure substances don't
• C. Pure substances are always solids, mixtures can be any state
• D. Pure substances are always elements, mixtures are always compounds

Correct answer: A

Rationale: Rationale: - Pure substances have a definite and constant composition, meaning they are made up of only one type of atom or molecule. This composition does not vary. - Mixtures, on the other hand, are composed of two or more substances physically combined. The components of a mixture can be present in varying proportions, leading to a variable composition. - Option A correctly distinguishes between pure substances and mixtures based on the fixed composition of pure substances and the variable composition of mixtures.

2. Neon (Ne). Both He and Ne belong to Group 18 (Noble Gases) due to their complete and stable outer electron shells.

• A. Electromagnetism
• B. Gravity
• C. Strong nuclear force
• D. Weak nuclear force

Correct answer: C

Rationale: Strong nuclear force. This incredibly powerful force overcomes the repulsive electrostatic force between protons and binds the nucleus together.

3. The fluid-filled sacs that cushion the brain within the skull are called:

• A. Meninges
• B. Cerebrospinal fluid
• C. Dura mater
• D. Arachnoid mater

Correct answer: B

Rationale: The correct answer is B: Cerebrospinal fluid. Cerebrospinal fluid is a clear, colorless fluid that surrounds the brain and spinal cord, acting as a cushion to protect the central nervous system from injury. Meninges (Option A) are the protective membranes that cover the brain and spinal cord, while the dura mater (Option C) and arachnoid mater (Option D) are specific layers of the meninges. However, cerebrospinal fluid is the fluid-filled sac that directly cushions the brain within the skull, making it the most appropriate answer for this question.

4. When light interacts with a perfectly smooth surface, like a mirror, the dominant interaction is:

• A. Refraction
• B. Diffraction
• C. Total internal reflection
• D. Specular reflection

Correct answer: D

Rationale: The correct answer is D: Specular reflection. When light interacts with a perfectly smooth surface like a mirror, it undergoes specular reflection, where the light rays are reflected at the same angle as the incident angle. Refraction (option A) occurs when light passes from one medium to another at an angle, causing it to change direction. Diffraction (option B) is the bending of light waves around obstacles or through small openings. Total internal reflection (option C) occurs when light traveling in a medium strikes the boundary with another medium at an angle greater than the critical angle, causing the light to reflect back into the original medium. In the case of a perfectly smooth surface, specular reflection is the dominant interaction as the light rays reflect in a single direction with minimal scattering or diffraction.

5. Simple columnar epithelium lining the small intestine is crucial for:

• A. Movement
• B. Support
• C. Absorption
• D. Insulation

Correct answer: C

Rationale: The correct answer is C: Absorption. The simple columnar epithelium lining the small intestine is crucial for absorption due to its structure and function. It has microvilli that increase the surface area available for nutrient absorption. This epithelium also contains specialized cells like goblet cells that secrete mucus to protect the lining and aid in the movement of materials. Movement (choice A) is more related to muscle tissue rather than epithelial tissue. Support (choice B) is usually provided by connective tissue rather than epithelial tissue. Insulation (choice D) is not a function of the simple columnar epithelium in the small intestine.

6. What is the main function of the large intestine?

• A. Break down food
• B. Absorb water
• C. Secrete digestive enzymes
• D. Store waste

Correct answer: B

Rationale: The correct answer is B: "Absorb water." The main function of the large intestine is to absorb water and electrolytes from the undigested food material that passes through it. This helps in the formation of solid waste or feces, which is then stored in the rectum until it is eliminated from the body. Breaking down food primarily occurs in the small intestine, while the large intestine focuses on reabsorbing water to prevent dehydration. Secreting digestive enzymes is mainly done by the pancreas and liver, not the large intestine.

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