Nokea
What property of matter explains why ice floats on water?
- A. Viscosity
- B. Density
- C. Buoyancy
- D. Surface tension
Correct Answer: C
Rationale: The correct answer is C, buoyancy. Ice floats on water due to buoyancy, a property of matter. When water freezes into ice, it becomes less dense than liquid water, causing it to float. This phenomenon occurs because the molecules in ice are more spread out compared to liquid water, resulting in ice being less dense and able to float on the surface.
Choice A, viscosity, is incorrect because viscosity refers to a fluid's resistance to flow, not its ability to float.
Choice B, density, is incorrect because while ice being less dense than water is the reason it floats, this choice does not explain the specific property that causes this phenomenon.
Choice D, surface tension, is incorrect as it pertains to the cohesive forces between molecules at the surface of a liquid, not the reason why ice floats on water.
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What are Merkel cells, located in the epidermis, specialized for?
- A. Melanin production
- B. Temperature sensation
- C. Touch perception
- D. Immune defense
Correct Answer: C
Rationale: Merkel cells are specialized touch receptors located in the epidermis of the skin. Their primary function is to perceive light touch and pressure. They play a crucial role in the sensory perception of touch stimuli. Option A, melanin production, is incorrect because Merkel cells are not involved in producing melanin. Option B, temperature sensation, is incorrect as Merkel cells are not specialized for sensing temperature. Option D, immune defense, is also incorrect as Merkel cells do not have a role in immune defense mechanisms.
Which term best describes the gradual change in a species over time in response to environmental pressures?
- A. Punctuated equilibrium (rapid bursts of evolution)
- B. Gradualism (slow and continuous change)
- C. Founder effect (genetic drift in a small population)
- D. Adaptive radiation (rapid diversification of a species)
Correct Answer: B
Rationale: A) Punctuated equilibrium refers to rapid bursts of evolution followed by long periods of stability, rather than gradual change over time in response to environmental pressures. B) Gradualism is the process by which species evolve through slow and continuous changes over time in response to environmental pressures. This gradual change can lead to the development of new traits and adaptations. C) Founder effect is a type of genetic drift that occurs when a small group of individuals establishes a new population, leading to a loss of genetic variation compared to the original population. It does not specifically describe the gradual change in a species over time. D) Adaptive radiation is the rapid diversification of a species into a variety of forms to exploit different ecological niches, but it does not specifically refer to the gradual change in response to environmental pressures. Therefore, the term that best describes the gradual change in a species over time in response to environmental pressures is 'Gradualism.'
What force keeps a car moving along a curved road?
- A. Gravitational force
- B. Normal force from the road
- C. Air resistance
- D. Friction between the tires and the road
Correct Answer: D
Rationale: The correct answer is D: Friction between the tires and the road. When a car travels along a curved road, the friction between the tires of the car and the road provides the necessary centripetal force required to keep the car moving in the curved path. This friction allows the tires to grip the road and prevent the car from sliding off the curve due to inertia or momentum. Choices A, B, and C are incorrect because gravitational force, normal force from the road, and air resistance do not play a significant role in keeping a car moving along a curved road. While these forces may have other effects on the car's motion, they are not the primary force responsible for maintaining the car's trajectory along a curve.
Identify the function NOT attributed to the lymphatic system.
- A. Fluid drainage from tissues
- B. Immune response via white blood cell production
- C. Nutrient transport throughout the body
- D. Waste removal through lymph nodes
Correct Answer: C
Rationale: A) Fluid drainage from tissues: This function is attributed to the lymphatic system. Lymphatic vessels collect excess fluid from tissues and return it to the bloodstream.
B) Immune response via white blood cell production: The lymphatic system plays a crucial role in the body's immune response by producing and transporting white blood cells, such as lymphocytes, which help fight infections.
C) Nutrient transport throughout the body: Nutrient transport is primarily carried out by the circulatory system (blood vessels), not the lymphatic system. The circulatory system transports nutrients, oxygen, and hormones to cells and removes waste products.
D) Waste removal through lymph nodes: The lymphatic system helps remove waste and toxins from the body by filtering lymph through lymph nodes, where harmful substances are trapped and destroyed by immune cells.
Therefore, the function NOT attributed to the lymphatic system is C) Nutrient transport throughout the body.
Osteoporosis is a condition that leads to weakened bones and an increased risk of fractures. Which hormone plays a key role in bone health and is often affected in osteoporosis?
- A. Estrogen
- B. Testosterone
- C. Thyroid hormone
- D. Insulin
Correct Answer: A
Rationale: Estrogen plays a crucial role in maintaining bone health by inhibiting bone resorption and promoting bone formation. In postmenopausal women, estrogen levels decrease, leading to an increased risk of osteoporosis due to accelerated bone loss. This hormonal imbalance contributes to weakened bones and an increased risk of fractures in individuals with osteoporosis. Testosterone and thyroid hormone do play roles in bone health, but estrogen has a more significant impact. Testosterone is more commonly associated with muscle mass and strength, while thyroid hormone regulates metabolism. Insulin is not directly involved in bone health and is not typically affected in osteoporosis.