Nokea
Which vitamin is necessary for calcium absorption?
- A. Vitamin A
- B. Vitamin C
- C. Vitamin D
- D. Vitamin K
Correct Answer: C
Rationale: Vitamin D is essential for the absorption of calcium in the intestines, aiding in the maintenance of strong bones and teeth. It helps regulate calcium and phosphorus levels in the body, supporting bone health and preventing conditions like osteoporosis. Vitamin A (Choice A) is important for vision and immune function, not specifically for calcium absorption. Vitamin C (Choice B) is crucial for collagen synthesis and immune function but is not directly involved in calcium absorption. Vitamin K (Choice D) plays a role in blood clotting and bone health, but it is not primarily responsible for calcium absorption.
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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.
What is the main function of the endocrine system?
- A. To fight infections
- B. To regulate body functions through hormones
- C. To produce red blood cells
- D. To transport oxygen
Correct Answer: B
Rationale: The main function of the endocrine system is to regulate various body functions by releasing hormones, which act as chemical messengers. These hormones help maintain homeostasis, regulate metabolism, growth, development, and other essential functions in the body. Option A is incorrect as fighting infections is primarily the role of the immune system, not the endocrine system. Option C is incorrect as the production of red blood cells mainly occurs in the bone marrow. Option D is incorrect as the transportation of oxygen is primarily carried out by the respiratory and circulatory systems. Therefore, option B is the correct answer as it accurately describes the primary role of the endocrine system.
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 maintain fluid balance
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. This process helps maintain the body's internal environment by regulating the balance of electrolytes, fluid levels, and eliminating metabolic waste products. Choices B, C, and D are incorrect because while the kidneys do produce urine, regulate blood pressure, and maintain fluid balance, their primary function within the urinary system is the filtration of waste from the blood.
What is the primary role of the stomach in the digestive system?
- A. To absorb nutrients
- B. To break down food
- C. To secrete digestive enzymes
- D. To store glucose
Correct Answer: B
Rationale: The primary role of the stomach in the digestive system is to break down food. It accomplishes this through the action of gastric acid and digestive enzymes, which work together to break down food into a semi-liquid mixture known as chyme. Option B, 'To break down food,' is the correct answer. Option A, 'To absorb nutrients,' is incorrect because absorption mainly occurs in the small intestine. Option C, 'To secrete digestive enzymes,' is partially correct as the stomach does secrete digestive enzymes, but its primary function is to break down food. Option D, 'To store glucose,' is incorrect as glucose storage primarily occurs in the liver and muscles, not the stomach.
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.