Nokea
What is the primary function of the digestive system?
- A. To break down food into nutrients
- B. To absorb oxygen
- C. To produce energy
- D. To regulate body temperature
Correct Answer: A
Rationale: The correct answer is A: 'To break down food into nutrients.' The primary function of the digestive system is to break down food into nutrients that can be absorbed by the body for energy, growth, and repair. The digestive system is not responsible for absorbing oxygen (Choice B), as that is the role of the respiratory system. While the digestion process does release energy from nutrients, the primary function is not to produce energy (Choice C), but rather to extract nutrients for energy production. Regulating body temperature (Choice D) is primarily handled by the thermoregulatory mechanisms in the body, such as the skin and sweat glands, not the digestive system.
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Which of the following vessels is responsible for pumping oxygenated blood to the body?
- A. Right ventricle
- B. Left ventricle
- C. Pulmonary artery
- D. Aorta
Correct Answer: D
Rationale: The aorta is the correct answer because it is responsible for pumping oxygenated blood from the heart to the rest of the body. The aorta is the main artery that carries blood away from the heart and distributes it to all parts of the body, providing oxygen and nutrients to the tissues. Choices A, B, and C are incorrect. The right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery, the left ventricle pumps oxygenated blood to the body through the aorta, and the pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation.
What does the phrase 'survival of the fittest' refer to?
- A. Organisms with the most complex anatomical structures are more likely to survive and reproduce.
- B. Organisms that demonstrate the best adaptations to their environment have a higher chance of survival and reproduction.
- C. All organisms have an equal probability of survival and reproductive success regardless of their traits.
- D. Only the strongest and most aggressive individuals within a population will survive and reproduce.
Correct Answer: B
Rationale: The phrase 'survival of the fittest' is often associated with the concept of natural selection, proposed by Charles Darwin. Natural selection is the process by which organisms best adapted to their environment are more likely to survive and reproduce, passing on their advantageous traits to the next generation. This process does not necessarily favor the most complex anatomical structures (option A) or the strongest and most aggressive individuals (option D). Instead, it emphasizes the importance of adaptations that enhance an organism's ability to survive and reproduce in a specific environment. Option C is incorrect because natural selection results in differential reproductive success based on an organism's traits, meaning that not all organisms have an equal probability of survival and reproductive success.
What is the primary source of energy entering most ecosystems?
- A. Chemical energy stored in bonds
- B. Thermal energy from the Earth's core
- C. Light energy from the sun
- D. Kinetic energy from wind and water
Correct Answer: C
Rationale: In most ecosystems, the primary source of energy is sunlight. This energy is captured by plants and other photosynthetic organisms through the process of photosynthesis. These organisms convert light energy into chemical energy stored in the bonds of organic molecules, such as glucose. This stored chemical energy is then passed on to other organisms in the ecosystem through the food chain, making sunlight the fundamental source of energy for most ecosystems. Thermal energy from the Earth's core (option B) is not a primary source of energy for ecosystems, as it is not readily accessible to most organisms. Kinetic energy from wind and water (option D) can play a role in some ecosystems, but it is not the primary source of energy. Chemical energy stored in bonds (option A) is a form of energy that is ultimately derived from the sun through photosynthesis, making it a product of the primary energy source rather than the primary source itself.
What happens to the speed of a sound wave when it travels from air to water?
- A. It increases because water is denser.
- B. It decreases because water is denser.
- C. It remains the same.
- D. Speed depends on the frequency, not the medium.
Correct Answer: B
Rationale: When a sound wave travels from air to water, the speed of sound decreases because sound travels faster in denser mediums. Water, being denser than air, causes the speed of sound to slow down. Choice A is incorrect because sound travels faster in denser mediums, so the speed would not increase. Choice C is incorrect because the speed of sound changes when transitioning between different mediums. Choice D is incorrect because while frequency does affect sound, the medium it travels through also plays a significant role in determining the speed of sound.
What is the recommended daily fiber intake for adults?
- A. 10 grams
- B. 25 grams
- C. 35 grams
- D. 50 grams
Correct Answer: B
Rationale: The recommended daily fiber intake for adults is around 25 grams for women and 38 grams for men. Fiber is essential for maintaining a healthy digestive system, preventing constipation, and reducing the risk of chronic diseases such as heart disease and diabetes. Consuming an adequate amount of fiber can also help with weight management and promote overall well-being. Option B is the correct answer based on the recommended daily intake guidelines for adults. Choices A, C, and D are incorrect because they do not align with the established guidelines for fiber intake in adults. 10 grams (choice A) is too low, 35 grams (choice C) is higher than the general recommendation, and 50 grams (choice D) is significantly above the recommended intake, which may lead to digestive issues in some individuals.