Nokea
What is the outermost layer of the dermis, rich in collagen and elastin fibers that provide elasticity to the skin?
- A. Papillary layer
- B. Reticular layer
- C. Stratum basale
- D. Stratum corneum
Correct Answer: B
Rationale: The correct answer is the reticular layer. This layer is the outermost layer of the dermis that contains abundant collagen and elastin fibers, providing elasticity to the skin. The papillary layer is located beneath the epidermis and is responsible for supplying nutrients to the epidermis, not the outermost layer. The stratum basale is the deepest layer of the epidermis where new skin cells are produced, not part of the dermis. The stratum corneum is the outermost layer of the epidermis composed of dead skin cells, not a layer of the dermis.
You may also like to solve these questions
Unlike the circulatory system, the lymphatic system does not have a pump. 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 primarily due to muscle contractions and breathing movements and also with the help of one-way valves within the vessels. The lymphatic system lacks a central pump like the heart; hence, it relies on the contraction of surrounding muscles and breathing movements to propel lymph fluid. One-way valves within the lymphatic vessels prevent backflow and ensure the unidirectional flow of lymph. Option A is incorrect as the lymphatic system does not rely on the pumping action of the heart. Option D is incorrect as the correct answer is the combination of muscle contractions, breathing movements, and one-way valves, not all the options provided.
What is the primary composition of the stratum corneum, the outermost layer of the epidermis?
- A. Keratinized dead cells
- B. Melanocytes
- C. Langerhans cells
- D. Merkel cells
Correct Answer: A
Rationale: The stratum corneum, the outermost layer of the epidermis, is primarily composed of keratinized dead cells. These cells are flattened, fully keratinized, and lack nuclei, serving a protective function for the skin. Melanocytes are responsible for producing melanin, providing skin pigmentation. Langerhans cells are involved in the immune response within the skin. Merkel cells are associated with sensory functions in the skin, particularly in touch sensations. Therefore, the correct answer is A as it accurately reflects the main constituent of the stratum corneum, which acts as a barrier against external factors.
When is work done on an object?
- A. Only when the object's velocity changes
- B. Only when a force is applied to the object
- C. Whenever there is a force exerted on the object causing displacement
- D. Only when the object is lifted vertically
Correct Answer: C
Rationale: Work is done on an object whenever a force causes displacement in the object's position. According to the work-energy principle, work is calculated as the force applied multiplied by the distance the object moves in the direction of the force. Therefore, work can occur whenever there is a force exerted on the object resulting in displacement, regardless of whether the object's velocity changes or it is lifted vertically. Choice A is incorrect because work can be done even without a change in velocity. Choice B is incorrect as work requires both force and displacement, not just the application of force. Choice D is incorrect because work is not limited to vertical lifting; it can happen in any direction as long as there is a force causing displacement.
What is the relationship between the speed of a wave, its frequency, and wavelength in a given medium?
- A. Speed = Frequency Wavelength
- B. Speed = Frequency · Wavelength
- C. Speed = Frequency + Wavelength
- D. Speed = Frequency - Wavelength
Correct Answer: A
Rationale: The speed of a wave in a given medium is determined by the product of its frequency and wavelength. This relationship is described by the formula: Speed = Frequency Wavelength. When a wave travels through a medium, the speed at which it propagates is directly proportional to both its frequency and wavelength. Therefore, to calculate the speed of the wave, you multiply the frequency of the wave by its wavelength. Choices B, C, and D are incorrect because speed is not determined by division, addition, or subtraction of frequency and wavelength; instead, it is determined by their multiplication in the given medium.
What is the term for the process of a gas changing directly into a solid?
- A. Condensation
- B. Deposition
- C. Sublimation
- D. Evaporation
Correct Answer: B
Rationale: The correct term for the process of a gas changing directly into a solid is deposition. During deposition, gas particles lose energy and transition directly into the solid state without passing through the liquid phase. Sublimation, on the other hand, is the process in which a solid changes directly into a gas without going through the liquid phase. Condensation is the process where gas changes into a liquid state. Evaporation, on the contrary, is the conversion of a liquid to a gas. Therefore, the correct answer is B, deposition.