What is the primary function of the immune system?
- A. To transport oxygen
- B. To fight infections
- C. To produce energy
- D. To regulate body temperature
Correct Answer: B
Rationale: The primary function of the immune system is to fight infections. It identifies and destroys pathogens like bacteria and viruses, protecting the body from harmful substances. While oxygen transportation is carried out by the respiratory system, energy production is mainly the role of the metabolic system, and body temperature regulation is managed by the thermoregulatory system. These functions are separate from the immune system's primary role of defending the body against infections.
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What is the primary function of red blood cells?
- A. Clotting blood
- B. Transporting oxygen
- C. Fighting infection
- D. Carrying hormones
Correct Answer: B
Rationale: The primary function of red blood cells, also known as erythrocytes, is to transport oxygen from the lungs to the body's tissues and organs. This is essential for cellular respiration and overall body functions. Red blood cells do not play a role in clotting blood, fighting infection, or carrying hormones. Choice A is incorrect because clotting blood is primarily done by platelets and other components of blood. Choice C is incorrect as fighting infection is a function mainly carried out by white blood cells. Choice D is incorrect because carrying hormones is primarily attributed to proteins like albumin and specific hormone-carrying proteins.
What is the primary function of the heart in the circulatory system?
- A. To filter blood
- B. To pump blood throughout the body
- C. To absorb oxygen
- D. To remove carbon dioxide
Correct Answer: B
Rationale: The correct answer is B: 'To pump blood throughout the body.' The primary function of the heart in the circulatory system is to pump blood, which carries oxygen and nutrients, throughout the body. Choice A, 'To filter blood,' is incorrect as the heart does not filter blood; that is primarily done by the kidneys. Choice C, 'To absorb oxygen,' is incorrect as the lungs are responsible for oxygen absorption. Choice D, 'To remove carbon dioxide,' is incorrect as the lungs facilitate the removal of carbon dioxide from the body.
What is the primary function of the kidneys in the urinary system?
- A. Regulating blood pressure
- B. Filtering blood to remove waste
- C. Producing red blood cells
- D. Regulating electrolyte balance
Correct Answer: B
Rationale: The primary function of the kidneys in the urinary system is to filter blood to remove waste products and excess fluids, which are then excreted as urine. Kidneys act as a filtration system, removing waste like urea, excess salts, and toxins. While the kidneys do play a role in regulating blood pressure by secreting renin and maintaining electrolyte balance by adjusting the levels of sodium, potassium, and other ions in the blood, their main and essential function is filtration and waste removal, making choice B the correct answer.
What is the main function of the nervous system?
- A. Transporting blood
- B. Protecting the body from infection
- C. Regulating body temperature
- D. Digesting food
Correct Answer: C
Rationale: The main function of the nervous system is to control and coordinate body activities by transmitting signals between different parts of the body and responding to internal and external stimuli. This allows for the regulation of body temperature, movement, sensory perception, and various other functions necessary for homeostasis. Choices A, B, and D are incorrect as they do not align with the primary role of the nervous system. Transporting blood is mainly carried out by the circulatory system, protecting the body from infection is a function of the immune system, and digesting food is the role of the digestive system.
What is the main function of the adrenal glands?
- A. Regulation of metabolism
- B. Production of bile
- C. Regulation of blood pressure
- D. Production of insulin
Correct Answer: C
Rationale: The main function of the adrenal glands is to produce hormones like adrenaline and cortisol. These hormones play a crucial role in regulating blood pressure, metabolism, and the body's stress response. While the adrenal glands do have some impact on metabolism, their primary function is not the direct regulation of metabolism. They are not involved in the production of bile or insulin. Therefore, the correct answer is the regulation of blood pressure.