Nokea
What is the role of platelets in the blood?
- A. Transport oxygen
- B. Fight infection
- C. Produce antibodies
- D. Clot blood
Correct Answer: D
Rationale: Platelets play a crucial role in blood clotting by forming clots to help stop bleeding. While red blood cells transport oxygen, white blood cells fight infection, and immune cells produce antibodies, platelets specifically function to prevent excessive bleeding by forming clots. Therefore, the correct answer is D. Choices A, B, and C are incorrect as they describe functions of other components of the blood, not platelets.
You may also like to solve these questions
Which of the following is a function of the kidneys?
- A. To produce digestive enzymes
- B. To filter waste from the blood
- C. To produce white blood cells
- D. To produce red blood cells
Correct Answer: B
Rationale: The correct answer is B: 'To filter waste from the blood.' The kidneys are vital organs responsible for filtering waste products from the blood, regulating fluid and electrolyte balance, and producing urine. Choice A is incorrect because the production of digestive enzymes primarily occurs in the pancreas and salivary glands. Choice C is incorrect as the production of white blood cells mainly takes place in the bone marrow and lymphatic system. Choice D is incorrect as the production of red blood cells occurs in the bone marrow.
Which of the following structures can serve as a passageway for both food and air?
- A. Esophagus
- B. Laryngopharynx
- C. Nasopharynx
- D. Trachea
Correct Answer: B
Rationale: The correct answer is the Laryngopharynx. It is a common passageway for both food and air. The Esophagus (Choice A) is solely for transporting food from the throat to the stomach. The Nasopharynx (Choice C) is primarily involved in the passage of air. The Trachea (Choice D) is responsible for conducting air to and from the lungs and does not play a role in the passage of food.
Which method is most suitable for measuring the volume of a cube?
- A. Triple beam balance
- B. Measuring wheel and mathematical formula
- C. Graduated cylinder
- D. Measuring wheel
Correct Answer: B
Rationale: The correct answer is B. To measure the volume of a cube, you need to use a mathematical formula that takes into account the dimensions of the cube, specifically the length of its sides. Using a measuring wheel alone or a triple beam balance is not suitable for determining the volume of a cube. A graduated cylinder is used to measure the volume of liquids, not geometric solids like cubes.
Which of the following statements regarding the pericardium is not correct?
- A. It allows for the heart to work in a relatively friction-free environment
- B. It is a single-walled layer around the heart
- C. It prevents overfilling of the heart with blood
- D. It protects and anchors the heart
Correct Answer: B
Rationale: The correct statement about the pericardium is that it is double-walled, not single-walled. Choice A is correct because the pericardium does allow the heart to work in a relatively friction-free environment, reducing friction during heartbeats. Choice C is correct as the pericardium helps prevent the overfilling of the heart with blood. Choice D is also correct as the pericardium serves to protect and anchor the heart in place within the chest cavity.
Which of the following does not describe a general trait of macromolecules?
- A. They can exist as single chains.
- B. They can be branched.
- C. They all contain carbon, hydrogen, and phosphorus.
- D. They are all used by the body.
Correct Answer: C
Rationale: The correct answer is C. While many macromolecules contain carbon, hydrogen, and phosphorus, not all of them do. For example, lipids, a type of macromolecule, may not contain phosphorus. Choice A and B describe structural features that macromolecules can exhibit, whether as single chains or branched forms. Choice D is incorrect as not all macromolecules are used by the body, such as synthetic polymers or certain non-digestible fibers.