What is the function of the stomach in the digestive system?

Correct Answer: B

Rationale: The correct answer is B: 'To break down food.' The stomach plays a crucial role in the digestive system by breaking down food using gastric acid and digestive enzymes. This process transforms the food into a semi-liquid mixture known as chyme, which is further digested in the small intestine. Choices A, C, and D are incorrect because the stomach does not primarily absorb nutrients, produce bile, or store waste. These functions are carried out by other organs in the digestive system such as the small intestine, liver, and large intestine, respectively.

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.

Correct Answer: B

Rationale: The correct answer is B: To absorb nutrients. The small intestine's main role in the digestive system is to absorb nutrients from digested food. It has specialized structures, such as villi and microvilli, that increase its surface area for efficient absorption of nutrients into the bloodstream. Choice A is incorrect because the small intestine does not primarily secrete digestive enzymes; that role is mainly carried out by the pancreas and other digestive organs. Choice C is incorrect because the small intestine primarily absorbs nutrients rather than breaking down food. Choice D is incorrect because the absorption of water primarily occurs in the large intestine, not the small intestine.

Correct Answer: A

Rationale: The correct answer is Vitamin C. Vitamin C is essential for the synthesis of collagen, a protein crucial for maintaining the structure and integrity of skin, blood vessels, and bones. It plays a key role in the hydroxylation of proline and lysine residues in collagen synthesis, which is necessary for the stability and strength of collagen fibers. Choice B: Vitamin D is essential for bone health and calcium absorption but is not directly involved in collagen synthesis. Choice C: Vitamin B12 is important for red blood cell formation and neurological function but is not directly related to collagen synthesis. Choice D: Vitamin K is necessary for blood clotting and bone metabolism but does not play a direct role in collagen synthesis.

Correct Answer: B

Rationale: The correct answer is B: 'To break down food.' The stomach plays a crucial role in the digestive system by breaking down food using gastric acid and digestive enzymes. This process transforms the food into a semi-liquid mixture known as chyme, which is further digested in the small intestine. Choices A, C, and D are incorrect because the stomach does not primarily absorb nutrients, produce bile, or store waste. These functions are carried out by other organs in the digestive system such as the small intestine, liver, and large intestine, respectively.

Correct Answer: B

Rationale: The correct answer is the Adrenal gland. The Adrenal glands, situated on top of the kidneys, are responsible for producing adrenaline. Adrenaline is a hormone that prepares the body for the fight-or-flight response during stress. Choice A, the Thyroid gland, is responsible for producing hormones that regulate metabolism, not adrenaline. Choice C, the Pituitary gland, regulates many of the body's functions by producing various hormones but is not responsible for adrenaline production. Choice D, the Pineal gland, produces melatonin, a hormone that regulates sleep-wake cycles, and is not responsible for adrenaline production.

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.

Correct Answer: B

Rationale: The large intestine's primary function is to absorb water from the remaining indigestible food matter that enters it from the small intestine. This absorption process helps in forming solid waste (feces) by compacting the material and preparing it for excretion. The large intestine does not secrete digestive enzymes, produce bile, or transport nutrients. Therefore, option B, 'To absorb water and form solid waste,' is the correct function of the large intestine in the digestive system.

Correct Answer: C

Rationale: The correct answer is C: Kidneys. The kidneys are the organs responsible for filtering and cleaning the blood. They remove waste products, regulate electrolyte levels, and help maintain fluid balance in the body through the production of urine. The other choices are incorrect because: A) Lungs are primarily responsible for gas exchange, not blood filtration. B) The heart is responsible for pumping blood, not filtering it. D) The liver plays a role in detoxification and metabolism, but it is not primarily responsible for filtering and cleaning the blood.