Nursing Elites

1. Antigenic variation, a common strategy used by some viruses, allows them to:

• A. Produce toxins
• B. Evade the immune system
• C. Survive outside a host
• D. Replicate rapidly

Correct answer: B

Rationale: Rationale: Antigenic variation is a strategy used by some viruses to evade the host's immune response. By constantly changing their surface antigens, viruses can avoid recognition and destruction by the immune system. This allows the virus to persist in the host and continue replicating, leading to prolonged infection and potential transmission to other hosts. Antigenic variation does not directly involve the production of toxins, survival outside a host, or rapid replication, making options A, C, and D incorrect in this context.

2. What is the difference between a germline mutation and a somatic mutation?

• A. Germline mutations are passed to offspring, while somatic mutations are not.
• B. Germline mutations occur in reproductive cells, while somatic mutations occur in body cells.
• C. Germline mutations only affect genes, while somatic mutations can affect any DNA.
• D. Germline mutations are always beneficial, while somatic mutations are always harmful.

Correct answer: B

Rationale: Rationale: - Germline mutations are changes in the DNA of reproductive cells (sperm or egg cells) and can be passed on to offspring, affecting all cells in the resulting organism. - Somatic mutations are changes in the DNA of non-reproductive cells (body cells) and are not passed on to offspring. These mutations only affect the cells that arise from the mutated cell. - Option A is incorrect because somatic mutations are not passed to offspring. - Option C is incorrect because both germline and somatic mutations can affect any DNA. - Option D is incorrect because the effects of mutations, whether germline or somatic, can be beneficial, harmful, or have no significant impact.

3. The two main divisions of the skeletal system are:

• A. Upper and lower body bones
• B. Axial and appendicular skeleton
• C. Long and short bones
• D. Compact and spongy bone

Correct answer: B

Rationale: The correct answer is B: Axial and appendicular skeleton. The skeletal system is divided into two main parts: the axial skeleton, which includes the skull, rib cage, and vertebral column, and the appendicular skeleton, which includes the bones of the arms, legs, shoulders, and hips. This division is based on the location and function of the bones in the body. The other options are incorrect as they do not represent the main divisions of the skeletal system. Understanding these divisions is important for studying the structure and function of the human skeletal system.

4. Bone is a type of

• A. Epithelial tissue
• B. Connective tissue
• C. Hard connective tissue
• D. Muscle tissue

Correct answer: C

Rationale: The correct answer is C: "Hard connective tissue." Bone is classified as hard connective tissue because it is composed of cells embedded in a matrix of mineralized collagen fibers, providing support and protection to the body. Epithelial tissue (A) covers body surfaces and lines cavities, while connective tissue (B) includes bone, cartilage, and blood. Muscle tissue (D) is responsible for movement and is not the same as bone tissue.

5. Which of the following is an example of a chemical change?

• A. Dissolving sugar in water
• B. Boiling water
• C. Rusting iron
• D. Crushing ice

Correct answer: C

Rationale: Rusting is a chemical reaction where iron reacts with oxygen and water to form iron oxide (rust).

6. The outermost layer of the skin, providing protection against pathogens and the environment, is the:

• A. Dermis
• B. Epidermis
• C. Hypodermis
• D. Stratum corneum (part of the epidermis)

Correct answer: D

Rationale: The correct answer is D, 'Stratum corneum (part of the epidermis).' The stratum corneum is the outermost layer of the epidermis, consisting of dead skin cells that provide a protective barrier against pathogens and environmental factors. The dermis is located beneath the epidermis and contains connective tissue, nerves, and blood vessels. The hypodermis is the deepest layer of the skin, consisting of fat and connective tissue. Understanding the layers of the skin and their functions is essential for comprehending the skin's role in protecting the body.

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