Nokea
Which of the following situations represents work being done on an object?
- A. Pushing against a wall without moving it
- B. Carrying a heavy object without lifting it
- C. Lifting a box to place it on a shelf
- D. Holding a book stationary in your hand
Correct Answer: C
Rationale: Work is defined as the product of the force applied to an object and the distance over which the force is applied. In the situation of lifting a box to place it on a shelf, work is being done on the object. This is because lifting the box involves applying a force over a distance (the height of the shelf). The force applied to lift the box results in work being done on the object by raising it against the force of gravity. Choices A, B, and D do not involve work being done on the object as they either do not involve movement against a force (A, D) or do not cover distance against a force (B).
You may also like to solve these questions
Which of the following accurately describes saltatory conduction?
- A. It is faster than normal nerve conduction
- B. It occurs from one node of Ranvier to the next
- C. It only occurs in myelinated neurons
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, 'All of the above.' Saltatory conduction is faster than normal nerve conduction, occurs from one node of Ranvier to the next, and is exclusive to myelinated neurons. This form of conduction allows for the rapid transmission of nerve impulses by the action potential jumping between the nodes of Ranvier in myelinated neurons, enhancing the efficiency of signal propagation along the axon. Choice A is correct as saltatory conduction is indeed faster than normal conduction. Choice B is accurate as it describes the mechanism of conduction 'jumping' from one node of Ranvier to the next. Choice C is correct because saltatory conduction occurs specifically in myelinated neurons where the myelin sheath insulates the axon except at the nodes of Ranvier, facilitating faster transmission of nerve impulses.
Which of the following best describes the term homeostasis?
- A. The ability to maintain a constant body temperature
- B. The ability to maintain a stable internal environment
- C. The ability to increase body temperature when cold
- D. The ability to regulate blood glucose levels
Correct Answer: B
Rationale: The correct answer is B, 'The ability to maintain a stable internal environment.' Homeostasis refers to the body's ability to regulate and maintain a stable internal environment, which includes variables like body temperature, pH levels, and fluid balance. It involves processes that help keep the body's internal conditions within a narrow range, despite external changes. While maintaining body temperature is a component of homeostasis, it is not the complete definition of the term. Choice C, 'The ability to increase body temperature when cold,' is incorrect as homeostasis aims to maintain stability rather than promoting temperature increases in response to external conditions. Choice D, 'The ability to regulate blood glucose levels,' is also incorrect as this is a specific function related to glucose homeostasis, which is a part of overall homeostatic processes but not the sole definition of homeostasis itself.
Dysentery is an infectious disease caused by which type of microbe?
- A. Helminth
- B. Bacteria
- C. Protozoan
- D. Fungus
Correct Answer: B
Rationale: The correct answer is B: Bacteria. Dysentery is typically caused by bacterial infections, such as Shigella, Campylobacter, or Escherichia coli. While parasites and protozoa can also cause similar symptoms, bacterial infections are the most common causes of dysentery. Choice A (Helminth) is incorrect as helminths are parasitic worms that typically cause different types of infections. Choice C (Protozoan) is incorrect as some protozoa like Entamoeba histolytica can cause dysentery, but bacterial infections are more common. Choice D (Fungus) is incorrect as fungal infections do not typically cause dysentery.
Which of the following blood vessels carries oxygenated blood from the lungs to the heart?
- A. Pulmonary vein
- B. Pulmonary artery
- C. Aorta
- D. Vena cava
Correct Answer: A
Rationale: The correct answer is A: Pulmonary vein. The pulmonary vein carries oxygenated blood from the lungs to the heart. It is essential to distinguish between the pulmonary vein (A) and the pulmonary artery (B) in this context. The pulmonary vein transports oxygenated blood, while the pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation. The aorta (C) functions as the main artery that delivers oxygenated blood from the heart to the body's tissues, while the vena cava (D) returns deoxygenated blood from the body to the heart.
Which of the following vessels is responsible for transporting blood from the heart to the lungs?
- A. Pulmonary vein
- B. Pulmonary artery
- C. Aorta
- D. Superior vena cava
Correct Answer: B
Rationale: The correct answer is B, Pulmonary artery. The pulmonary artery carries deoxygenated blood from the heart's right ventricle to the lungs for oxygenation. This blood then undergoes the gas exchange process in the lungs, where carbon dioxide is removed, and oxygen is absorbed. The pulmonary vein, identified in choice A, carries oxygenated blood from the lungs back to the heart, which is the opposite direction of the blood flow specified in the question. Choice C, Aorta, is responsible for carrying oxygen-rich blood from the heart's left ventricle to the rest of the body, not to the lungs. Choice D, Superior vena cava, returns deoxygenated blood from the upper body to the heart's right atrium, but it does not transport blood specifically to the lungs as requested in the question.