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What is the primary function of red blood cells in the cardiovascular system?
- A. To transport oxygen throughout the body.
- B. To fight infection and disease.
- C. To help regulate blood clotting.
- D. To remove waste products from the body.
Correct Answer: A
Rationale: Red blood cells, also known as erythrocytes, play a crucial role in the cardiovascular system by primarily transporting oxygen from the lungs to the body's tissues and organs. This essential function is carried out through the interaction of hemoglobin, a protein within red blood cells, which binds to oxygen in the lungs and releases it in the body's tissues. Choices B, C, and D are incorrect. Red blood cells are not actively involved in fighting infections, regulating blood clotting, or eliminating waste products from the body.
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In physics, what does the term 'net force' refer to?
- A. Total force acting on an object
- B. Force due to gravity
- C. Force in motion
- D. Force of friction
Correct Answer: A
Rationale: In physics, the term 'net force' refers to the total force acting on an object, considering all individual forces acting on it. It is crucial in determining the object's motion and acceleration as it represents the overall force applied to the object. Choice B, 'Force due to gravity,' is incorrect as it refers to a specific force acting on an object due to gravity. Choice C, 'Force in motion,' is incorrect as it does not define the concept of net force. Choice D, 'Force of friction,' is incorrect as it specifically refers to the force opposing motion when two surfaces are in contact.
When a blockage forms in a coronary artery, reducing blood flow to the heart muscle, this condition is called:
- A. Atherosclerosis
- B. Myocardial infarction
- C. Angina pectoris
- D. Heart murmur
Correct Answer: B
Rationale: A myocardial infarction, commonly known as a heart attack, occurs when a blockage forms in a coronary artery, leading to reduced blood flow to the heart muscle. Atherosclerosis refers to the buildup of plaque in the arteries, which can lead to blockages but is not the name for this specific condition. Angina pectoris is chest pain or discomfort due to inadequate blood supply to the heart muscle, which is a precursor to a heart attack but not the name for this condition. A heart murmur is an abnormal sound heard during a heartbeat, often due to turbulent blood flow, and is not related to a blockage in a coronary artery.
What are the fluid-filled sacs that cushion the brain within the skull called?
- A. Meninges
- B. Cerebrospinal fluid
- C. Dura mater
- D. Arachnoid mater
Correct Answer: B
Rationale: The correct answer is B, cerebrospinal fluid. Cerebrospinal fluid acts as a shock absorber, protecting the brain from impact and providing nutrients to brain cells. Meninges are the three protective layers of tissue that surround the brain and spinal cord. Dura mater and arachnoid mater are specific layers of the meninges, not the fluid-filled sacs that cushion the brain.
What property of a substance remains constant regardless of its location in the universe?
- A. Mass
- B. Weight
- C. Density
- D. Volume
Correct Answer: A
Rationale: Mass is a measure of the amount of matter in an object and remains constant regardless of its location in the universe. Weight, on the other hand, is the force of gravity acting on an object and can vary depending on the gravitational pull at different locations. Density and volume can also change based on the environment in which an object is placed, making mass the property that remains constant universally. Therefore, the correct answer is mass. Weight changes with the gravitational force of a particular location, density varies with mass and volume, and volume can change depending on the shape or size of the object.
What is the formula to calculate work?
- A. Work = Force Distance
- B. Work = Mass Velocity
- C. Work = Power Time
- D. Work = Energy · Time
Correct Answer: A
Rationale: Work is defined as the product of the force applied to an object and the distance over which the force is applied. The formula to calculate work is represented by Work = Force Distance, where force is the applied force on an object and distance is the displacement over which the force is applied. Therefore, the correct formula to calculate work is Work = Force Distance.
Choice B, 'Work = Mass Velocity,' is incorrect because work involves force and distance, not mass and velocity. Choice C, 'Work = Power Time,' is incorrect because work is not directly calculated using power and time. Choice D, 'Work = Energy · Time,' is incorrect because work is not typically calculated by dividing energy by time; rather, it involves the product of force and distance.