Which of the following organs is involved in the immune system?

Correct Answer: C

Rationale: The appendix is involved in the immune system as it is believed to play a role in maintaining and protecting beneficial gut bacteria, especially after gastrointestinal illnesses. This helps in restoring the balance of intestinal bacteria crucial for immune function. The heart (Choice A), bronchi (Choice B), and esophagus (Choice D) are not directly involved in the immune system's functions. The heart pumps blood, the bronchi are part of the respiratory system, and the esophagus is responsible for transporting food to the stomach.

Correct Answer: C

Rationale: The appendix is involved in the immune system as it is believed to play a role in maintaining and protecting beneficial gut bacteria, especially after gastrointestinal illnesses. This helps in restoring the balance of intestinal bacteria crucial for immune function. The heart (Choice A), bronchi (Choice B), and esophagus (Choice D) are not directly involved in the immune system's functions. The heart pumps blood, the bronchi are part of the respiratory system, and the esophagus is responsible for transporting food to the stomach.

Correct Answer: B

Rationale: The primary function of the heart is to pump oxygenated blood and nutrients throughout the body, supplying cells with vital substances. Choice A is incorrect as the kidneys are responsible for filtering blood. Choice C is incorrect as waste removal is primarily handled by organs like the kidneys and liver. Choice D is incorrect as regulating body temperature is mainly controlled by mechanisms such as sweating and shivering, not the heart.

Correct Answer: B

Rationale: The correct answer is B: Absorbing water and forming solid waste. The large intestine plays a crucial role in absorbing water from the remaining indigestible food matter and forming solid waste (feces) to be excreted from the body. This process helps in maintaining the body's fluid balance and eliminating waste efficiently. Choices A, C, and D are incorrect because the large intestine is not primarily responsible for absorbing nutrients, breaking down fats, or secreting digestive enzymes. These functions are mainly carried out in the small intestine.

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.

Correct Answer: A

Rationale: The correct answer is A: To control breathing and heart rate. The medulla oblongata is a vital part of the brainstem responsible for regulating essential functions such as breathing, heart rate, and blood pressure. These functions are crucial for maintaining life, and the medulla oblongata plays a key role in ensuring the body's survival. Choices B, C, and D are incorrect because regulating body temperature is primarily controlled by the hypothalamus, coordinating voluntary movements is associated with the cerebellum and motor cortex, and processing sensory information is related to the thalamus and sensory cortex, not the medulla oblongata.

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 Golgi apparatus is an organelle responsible for packaging and distributing proteins and lipids within the cell. It modifies, sorts, and packages these molecules into vesicles for transportation to their final destinations, either within the cell or outside of it. The Golgi apparatus plays a crucial role in the secretory pathway of cells, ensuring that proteins are properly processed and directed to where they are needed. Ribosomes are responsible for protein synthesis, not packaging and distributing proteins. The endoplasmic reticulum is involved in protein synthesis and folding but not primarily in packaging and distributing proteins. Mitochondria are known as the powerhouse of the cell and are responsible for generating energy in the form of ATP through cellular respiration, not packaging and distributing proteins.

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.