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What is the role of the alveoli in the lungs?
- A. To filter blood
- B. To exchange gases
- C. To transport nutrients
- D. To store oxygen
Correct Answer: B
Rationale: The alveoli in the lungs are tiny air sacs responsible for the exchange of oxygen and carbon dioxide during breathing. Oxygen from inhaled air diffuses into the bloodstream through the alveoli, while carbon dioxide produced by cells is removed from the blood and exhaled out of the body through the alveoli. This gas exchange process is essential for the body to obtain oxygen and get rid of carbon dioxide, supporting cellular functions and maintaining overall health. Choices A, C, and D are incorrect because the alveoli do not filter blood, transport nutrients, or store oxygen. Their main function is gas exchange.
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What is the main function of the respiratory system?
- A. To transport nutrients
- B. To regulate body temperature
- C. To absorb oxygen and remove carbon dioxide
- D. To produce energy
Correct Answer: C
Rationale: The main function of the respiratory system is to absorb oxygen from the air into the bloodstream and remove carbon dioxide from the body. Oxygen is essential for cellular respiration, the process through which cells generate energy. Carbon dioxide is a waste product expelled during this process. Choice A, 'To transport nutrients,' is incorrect as the respiratory system is not primarily responsible for transporting nutrients. Choice B, 'To regulate body temperature,' is incorrect as the respiratory system's main role is not temperature regulation. Choice D, 'To produce energy,' is incorrect because while oxygen obtained through respiration is used in the energy production process, the respiratory system itself does not directly produce energy.
What is the primary function of the integumentary system?
- A. Protecting the body from external damage
- B. Regulating body temperature
- C. Producing vitamin D
- D. Producing red blood cells
Correct Answer: A
Rationale: The correct answer is A: Protecting the body from external damage. The primary function of the integumentary system, which includes the skin, hair, and nails, is to act as a physical barrier that protects the body from external damage such as pathogens, UV radiation, and mechanical injuries. While the integumentary system does play roles in regulating body temperature and producing vitamin D, its main and most crucial function is to provide a protective shield for the body. Choices B, C, and D are incorrect because although the integumentary system contributes to regulating body temperature and producing vitamin D, as well as housing cells involved in the immune response, its primary role is protection.
What is the primary function of the kidneys in the urinary system?
- A. To filter waste from the blood
- B. To produce urine
- C. To regulate blood pressure
- D. To absorb nutrients
Correct Answer: A
Rationale: The correct answer is A: 'To filter waste from the blood.' The primary function of the kidneys in the urinary system is to filter waste products and excess substances from the blood, forming urine, which is then excreted from the body. Kidneys play a crucial role in maintaining the body's overall balance by filtering out waste, regulating fluid levels, and helping in the elimination of toxins. Choices B, C, and D are incorrect because while the kidneys do produce urine, regulate blood pressure, and help in nutrient absorption indirectly, their primary function is the filtration of waste from the blood.
What is the primary function of the skin?
- A. To regulate body temperature
- B. To protect the body from external damage
- C. To produce vitamin D
- D. To produce red blood cells
Correct Answer: B
Rationale: The primary function of the skin is to protect the body from external damage. While the skin also helps regulate body temperature and produces vitamin D in response to sunlight, its main role is to act as a barrier against harmful external factors, such as pathogens and physical injuries. Choices A, C, and D are incorrect because although the skin does play a role in regulating body temperature and producing vitamin D, its primary function is providing protection against external threats.
What is the primary function of the digestive system?
- A. To transport oxygen
- B. To break down food and absorb nutrients
- C. To produce hormones
- D. To transport blood
Correct Answer: B
Rationale: The primary function of the digestive system is to break down food into smaller molecules and absorb nutrients such as vitamins, minerals, carbohydrates, proteins, and fats. These nutrients are then utilized by the body for energy, growth, and repair. The digestive system plays a crucial role in the process of extracting essential components from food and distributing them to the body's cells through the bloodstream. Choices A, C, and D are incorrect because transporting oxygen, producing hormones, and transporting blood are functions associated with other body systems like the respiratory system, endocrine system, and circulatory system, respectively, not the digestive system.