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. Describe the concept of inertia in terms of Newton's first law.

• A. Objects in motion tend to remain in motion unless acted upon by an external force
• B. Objects at rest tend to remain at rest unless acted upon by an external force
• C. An object's resistance to a change in its state of motion
• D. The force required to lift an object

Correct answer: c

Rationale: Inertia refers to an object's tendency to maintain its current state of motion (either at rest or in motion) unless acted upon by an external force.

3. A collection of organs working together to perform a specific physiological function is known as a(n):

• A. Tissue
• B. Organ system
• C. Organelle
• D. Organ

Correct answer: B

Rationale: The correct answer is B: Organ system. An organ system is a group of organs that work together to carry out a specific function in the body. While an organ is made up of different types of tissues that work together, an organ system involves multiple organs collaborating to perform more complex tasks. Tissues (option A) are groups of similar cells working together, organelles (option C) are structures within cells that have specific functions, and organs (option D) are made up of tissues and perform specific functions, but the term 'organ system' specifically refers to a higher level of organization involving multiple organs working in coordination.

4. A rocket engine expels hot gases backwards. What principle explains the rocket's forward motion?

• A. Newton's first law of motion
• B. Newton's second law of motion
• C. Newton's third law of motion
• D. Law of conservation of energy

Correct answer: C

Rationale: The hot gases expelled backwards exert a force on the rocket in the opposite direction (forward), propelling it upwards according to the action-reaction principle.

5. Dense irregular connective tissue, found in tendons and ligaments, provides:

• A. Flexibility
• B. Lubrication
• C. Insulation
• D. Tensile strength

Correct answer: D

Rationale: The correct answer is D: 'Tensile strength.' Dense irregular connective tissue is composed of tightly packed collagen fibers arranged in a random pattern, providing resistance to tension forces. This structural arrangement is ideal for tendons and ligaments, as they need to withstand pulling and stretching forces. 'Flexibility' (A) is more characteristic of elastic fibers, 'Lubrication' (B) is provided by synovial fluid in joints, and 'Insulation' (C) is typically associated with adipose tissue. Therefore, tensile strength is the primary function of dense irregular connective tissue in tendons and ligaments.

6. Entropy (S) is a thermodynamic property related to the system's disorder. According to the second law of thermodynamics, in a spontaneous process:

• A. The total entropy of the system and surroundings increases.
• B. The total entropy of the system and surroundings decreases.
• C. The total entropy of the system remains constant.
• D. The total entropy of the surroundings increases, while the system's entropy decreases.

Correct answer: A

Rationale: Entropy is a measure of a system's disorder or randomness. According to the second law of thermodynamics, in a spontaneous process, the total entropy of the system and surroundings increases, leading to a higher level of disorder or randomness. This increase in total entropy is consistent with the idea that systems tend towards higher entropy states over time. Therefore, option A is correct because it aligns with the principle that the total entropy of a closed system, including both the system and its surroundings, will increase in a spontaneous process.

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