Which of the following is responsible for transporting oxygen in the blood?
- A. White blood cells
- B. Red blood cells
- C. Platelets
- D. Plasma
Correct Answer: B
Rationale: Red blood cells are responsible for transporting oxygen in the blood. Hemoglobin, a protein found in red blood cells, binds to oxygen in the lungs and carries it to tissues throughout the body. White blood cells are involved in the immune system's defense mechanisms against infections, platelets help in blood clotting, and plasma is the liquid component of blood that carries various substances like nutrients, hormones, and waste products.
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Which organ produces bile to aid in digestion?
- A. Pancreas
- B. Liver
- C. Gallbladder
- D. Stomach
Correct Answer: B
Rationale: The correct answer is B: Liver. The liver produces bile, which is stored in the gallbladder and released into the small intestine to aid in the digestion and absorption of fats. The pancreas secretes digestive enzymes, not bile. The gallbladder stores bile but does not produce it. The stomach produces gastric juices, not bile, to aid in digestion.
Which of the following bones belongs to the category of long bones?
- A. Femur
- B. Ribs and cranial bones
- C. Sesamoid
- D. Vertebrae and hip bones
Correct Answer: A
Rationale: The correct answer is A: Femur. Long bones are characterized by their elongated shape, with examples including the femur, humerus, and tibia. These bones are essential for support, movement, and bone marrow production. Choice B, 'Ribs and cranial bones,' consists of flat bones, not long bones. Choice C, 'Sesamoid,' refers to small bones embedded within tendons and do not fall under the category of long bones. Choice D, 'Vertebrae and hip bones,' includes irregular bones that provide structural support and protection for vital organs, but they are not classified as long bones.
What is the main function of white blood cells?
- A. Transport oxygen
- B. Fight infection
- C. Produce antibodies
- D. Regulate body temperature
Correct Answer: B
Rationale: The main function of white blood cells is to fight infection, making choice B the correct answer. White blood cells are a crucial component of the immune system, working to defend the body against pathogens and foreign invaders. Choices A, C, and D are incorrect because white blood cells do not primarily transport oxygen, produce antibodies, or regulate body temperature. While some blood cells are involved in these functions, the primary role of white blood cells is to combat infections and maintain the body's immune response.
Which of the following structures is responsible for producing insulin?
- A. Liver
- B. Pancreas
- C. Gallbladder
- D. Spleen
Correct Answer: B
Rationale: The correct answer is B: Pancreas. The pancreas is the organ responsible for producing insulin. Insulin is a hormone that helps regulate blood sugar levels by allowing cells to take in glucose from the bloodstream. The liver (choice A) plays a role in regulating blood sugar levels through glycogen storage and release but does not produce insulin. The gallbladder (choice C) stores bile produced by the liver to aid in digestion and has no direct involvement in insulin production. The spleen (choice D) is involved in immune function and blood storage but not in the production of insulin.
Where is keratin found?
- A. It is a protein-digesting enzyme released by the stomach.
- B. It is released in the neuromuscular junction.
- C. It is a protein found in the hypodermis.
- D. It is a protein found in hair.
Correct Answer: D
Rationale: Keratin is a structural protein found in hair, skin, and nails, providing strength and protection. It forms the main structural component of hair, making choice D the correct answer. Choices A, B, and C are incorrect because keratin is not an enzyme released by the stomach, not released in the neuromuscular junction, and not found in the hypodermis. Remember that keratin is primarily associated with structural support in epithelial cells.