Nokea
Which type of blood cell is responsible for carrying oxygen?
- A. White blood cell
- B. Red blood cell
- C. Platelet
- D. Plasma
Correct Answer: B
Rationale: The correct answer is B: Red blood cell. Red blood cells, also known as erythrocytes, are responsible for carrying oxygen from the lungs to the body's tissues. They contain hemoglobin, a protein that binds to oxygen and transports it throughout the body. White blood cells (Choice A) are part of the immune system and help fight infections, not involved in carrying oxygen. Platelets (Choice C) are responsible for blood clotting, not oxygen transport. Plasma (Choice D) is the liquid component of blood that carries various substances like nutrients and waste products, but it does not directly carry oxygen.
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What is the role of the diaphragm in respiration?
- A. To regulate air pressure in the lungs
- B. To contract and expand the lungs
- C. To store oxygen
- D. To break down carbon dioxide
Correct Answer: B
Rationale: The correct answer is B. The diaphragm plays a crucial role in respiration by contracting and expanding the lungs. When the diaphragm contracts, it moves downward, creating more space in the chest cavity and allowing the lungs to expand. This expansion leads to a decrease in pressure inside the lungs, causing air to rush in. When the diaphragm relaxes, it moves back up, decreasing the space in the chest cavity and causing the lungs to deflate. This action increases the pressure in the lungs, leading to air being pushed out. Therefore, the diaphragm's main function is to facilitate the inhalation and exhalation of air by contracting and expanding the lungs. Choices A, C, and D are incorrect because the diaphragm's primary function is not to regulate air pressure in the lungs, store oxygen, or break down carbon dioxide. Instead, its main purpose is to aid in the mechanical process of breathing.
How many neutrons and electrons could a negative ion of sulfur have?
- A. 16 neutrons, 16 electrons
- B. 16 neutrons, 17 electrons
- C. 17 neutrons, 16 electrons
- D. 17 neutrons, 17 electrons
Correct Answer: B
Rationale: A negative ion of sulfur would have 16 protons and 17 electrons since it gains one electron. The number of neutrons in an ion does not change, so the neutrons would remain at 16. Therefore, the correct answer is 16 neutrons and 17 electrons, which corresponds to choice B. Choice A is incorrect as it does not account for the extra electron gained by the negative ion. Choices C and D are incorrect because they propose a change in the number of neutrons, which is not affected by the ionization process.
Which of the following structures helps filter pathogens from the blood?
- A. Lymph nodes
- B. Kidneys
- C. Spleen
- D. Pancreas
Correct Answer: C
Rationale: The spleen is the correct answer. The spleen is a vital organ in the immune system responsible for filtering pathogens from the blood. It contains specialized immune cells that aid in recognizing and eliminating harmful substances. Additionally, the spleen plays a role in recycling old red blood cells. Choices A, B, and D are incorrect. Lymph nodes primarily filter lymph fluid, not blood. Kidneys are involved in filtering waste and regulating fluid balance, not specifically filtering pathogens from the blood. The pancreas functions in hormone regulation and digestion, unrelated to filtering pathogens from the blood.
Which of the following joints is an example of a hinge joint?
- A. Hip joint
- B. Elbow joint
- C. Shoulder joint
- D. Knee joint
Correct Answer: B
Rationale: The correct answer is B: Elbow joint. A hinge joint allows movement primarily in one plane, enabling bending and straightening actions. The elbow joint specifically functions as a hinge joint, facilitating the bending and straightening of the arm. The other options, such as the hip joint (A), shoulder joint (C), and knee joint (D), are not examples of hinge joints as they allow movement in multiple planes with more complex motions.
Which of the following statements regarding macrophages is incorrect?
- A. They are found abundantly in the blood
- B. They are larger than neutrophils
- C. They are long-lived
- D. They are made in the bone marrow as monocytes, called macrophages once they reach organs
Correct Answer: A
Rationale: The correct answer is A. Macrophages are not found abundantly in the blood; they are present in tissues and organs. Macrophages are tissue-resident immune cells that play a key role in immune responses and are derived from monocytes produced in the bone marrow. Choice B is correct as macrophages are larger than neutrophils. Choice C is correct as macrophages are long-lived cells. Choice D is correct as macrophages originate in the bone marrow as monocytes and differentiate into macrophages once they migrate to various tissues and organs.