Nursing Elites

1. How does sunscreen protect the skin from harmful ultraviolet (UV) rays?

• A. By reflecting UV rays away from the skin
• B. By absorbing UV rays and converting them to heat
• C. By blocking UV rays completely
• D. By stimulating melanin production

Correct answer: B

Rationale: Sunscreen works by absorbing UV rays and converting them to heat. This mechanism helps to prevent the UV rays from penetrating the skin and causing damage such as sunburn, premature aging, and skin cancer. Reflecting UV rays away from the skin (option A) is not the primary function of sunscreen. While sunscreen does block UV rays, it does not do so completely (option C) as some UV rays may still penetrate the skin. Sunscreen does not stimulate melanin production (option D) as a means of protecting the skin from UV rays.

2. What happens during expiration?

• A. The diaphragm contracts and the thoracic cavity expands.
• B. The diaphragm relaxes and the thoracic cavity contracts.
• C. The thoracic cavity expands, increasing pressure.
• D. The diaphragm relaxes and moves upward.

Correct answer: B

Rationale: The correct answer is B. During expiration, the diaphragm relaxes, causing the thoracic cavity to contract. As the thoracic cavity decreases in size, the pressure inside the lungs increases, leading to air flowing out of the lungs. This process helps to expel carbon dioxide-rich air from the body. Choices A, C, and D are incorrect. In choice A, the diaphragm contracting and the thoracic cavity expanding describes inspiration, not expiration. Choice C is incorrect because during expiration, the thoracic cavity actually decreases in size. Choice D is incorrect as the diaphragm moving upward is not a typical movement associated with expiration.

3. Which of the following is NOT a function of progesterone in the female reproductive system?

• A. expression of secondary sexual characteristics, such as enlarged breasts
• B. stimulation of milk production in the breasts
• C. regulation and preparation of the endometrial lining of the uterus for potential pregnancy
• D. inhibition of contractions of the uterus as the ovum is released

Correct answer: A

Rationale: Progesterone plays a key role in the regulation and preparation of the endometrial lining of the uterus for potential pregnancy. It also inhibits contractions of the uterus as the ovum is released and stimulates milk production in the breasts. However, the expression of secondary sexual characteristics, such as enlarged breasts, is primarily influenced by estrogen, not progesterone. Therefore, choice A is the correct answer as it is not a function directly attributed to progesterone in the female reproductive system.

4. Which structure helps regulate body temperature by constricting or dilating in response to temperature changes?

• A. Sebaceous glands
• B. Hair follicles
• C. Sweat glands
• D. Langerhans cells

Correct answer: C

Rationale: Sweat glands play a crucial role in regulating body temperature by producing sweat that evaporates from the skin surface. This evaporation cools the body when it is hot and helps to maintain a stable internal temperature. Sebaceous glands produce oil to lubricate the skin, hair follicles are responsible for hair growth, and Langerhans cells are a type of immune cell in the skin. Therefore, the correct answer is 'Sweat glands' as they are specifically designed to respond to temperature changes by constricting or dilating to help regulate body temperature.

5. Which of the following is NOT true about fossils?

• A. They can provide evidence for the order of appearance of different species
• B. They can be used to estimate the age of rocks and layers
• C. They can tell us about the behavior of extinct organisms
• D. They are always perfectly preserved

Correct answer: D

Rationale: A) This statement is true. Fossils can provide evidence for the order of appearance of different species through the study of the fossil record. B) This statement is true. Fossils can be used to estimate the age of rocks and layers through relative dating methods such as stratigraphy and absolute dating methods like radiometric dating. C) This statement is true. Fossils can provide information about the behavior of extinct organisms through the study of their preserved remains and traces. D) This statement is NOT true. Fossils are not always perfectly preserved. In many cases, fossils are incomplete, fragmented, or altered over time due to geological processes. The level of preservation can vary depending on factors such as the type of organism, the environment in which it lived, and the processes involved in fossilization.

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