Nursing Elites

1. How does lymph move through the lymphatic vessels?

• A. By the pumping action of the heart
• B. Due to muscle contractions and breathing movements
• C. Through one-way valves within the vessels
• D. All of the above

Correct answer: C

Rationale: Lymph moves through the lymphatic vessels due to the presence of one-way valves within the vessels. These valves prevent the backflow of lymph and help propel the fluid forward as muscles contract and relax or due to breathing movements. Unlike blood circulation, the lymphatic system does not rely on the pumping action of the heart to move lymph. Choice A is incorrect because lymphatic circulation does not depend on the pumping action of the heart. Choice B is partly correct as muscle contractions and breathing movements do assist in propelling lymph, but the primary mechanism is the presence of one-way valves within the vessels, making choice C the most accurate answer. Choice D is incorrect as not all options listed contribute to how lymph moves through the lymphatic vessels.

2. What are the cellular functions of cilia and flagella?

• A. Cilia and flagella are responsible for cell movement.
• B. Cilia and flagella synthesize proteins.
• C. Cilia and flagella help protect the cell from its environment.
• D. Cilia and flagella have enzymes that help with digestion.

Correct answer: A

Rationale: Cilia and flagella are microtubule-based structures found on the surface of many eukaryotic cells. Their primary function is to facilitate cell movement. Cilia are short, numerous, and move in coordinated waving motions to move substances along the cell's surface. Flagella are longer and usually limited to one or a few per cell, providing a propeller-like movement for the cell. Both cilia and flagella aid in cell motility and are essential for various cellular functions, primarily involved in cell movement rather than protein synthesis, protection, or digestion. Therefore, choice A is correct as it accurately describes the primary function of cilia and flagella. Choices B, C, and D are incorrect as cilia and flagella are not involved in protein synthesis, cell protection, or digestion in cells.

3. What happens to the work done on an object when the angle between the force and displacement is 90 degrees?

• A. Maximum work is done
• B. No work is done
• C. Minimum work is done
• D. Work is infinite

Correct answer: B

Rationale: When the angle between the force and displacement is 90 degrees, the work done is given by the formula W = F * d * cos(theta), where theta is the angle between the force and displacement vectors. Since cos(90 degrees) = 0, the work done becomes zero. This means that no work is done on the object when the angle between the force and displacement is 90 degrees. Choice A is incorrect because maximum work is done when the force and displacement are in the same direction (theta = 0 degrees). Choice C is incorrect as minimum work is done when the force and displacement are parallel (theta = 0 degrees), not perpendicular. Choice D is incorrect because work cannot be infinite; it depends on the force, displacement, and the cosine of the angle between them.

4. 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: 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.

5. What information can be obtained directly from the element's atomic number?

• A. Its atomic mass
• B. Its position on the periodic table
• C. Its number of neutrons
• D. Its chemical properties

Correct answer: B

Rationale: The atomic number of an element represents the number of protons in the nucleus of an atom. This number determines the element's unique identity and its position on the periodic table. The atomic mass (option A) is not directly determined by the atomic number but is a weighted average of the isotopes of an element. The number of neutrons (option C) is not directly provided by the atomic number but can be calculated by subtracting the atomic number from the atomic mass. The position on the periodic table (option B) is directly related to the atomic number, as elements are arranged in order of increasing atomic number. The chemical properties of an element (option D) are influenced by the number of protons in the nucleus, which is determined by the atomic number.

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