In the context of cholesterol levels, LDL cholesterol is often referred to as:
- A. HDL or "good" cholesterol.
- B. LDL or "bad" cholesterol.
- C. Total cholesterol, encompassing both LDL and HDL.
- D. VLDL, a type of triglyceride transported in the bloodstream.
Correct Answer: B
Rationale: LDL cholesterol is often referred to as "bad" cholesterol because high levels of LDL can lead to plaque buildup in the arteries, increasing the risk of heart disease and stroke. LDL cholesterol is considered harmful as it contributes to the formation of plaque in blood vessels, whereas HDL cholesterol helps remove LDL from the arteries. Choice A is incorrect because HDL is known as "good" cholesterol, which helps remove LDL cholesterol from the bloodstream. Choice C is incorrect as it refers to total cholesterol, which includes LDL, HDL, and other lipids. Choice D is incorrect as VLDL is a different type of lipoprotein that carries triglycerides and is not specifically related to LDL cholesterol.
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Identify the function NOT attributed to the lymphatic system.
- A. Fluid drainage from tissues
- B. Immune response via white blood cell production
- C. Nutrient transport throughout the body
- D. Waste removal through lymph nodes
Correct Answer: C
Rationale: A) Fluid drainage from tissues: This function is attributed to the lymphatic system. Lymphatic vessels collect excess fluid from tissues and return it to the bloodstream.
B) Immune response via white blood cell production: The lymphatic system plays a crucial role in the body's immune response by producing and transporting white blood cells, such as lymphocytes, which help fight infections.
C) Nutrient transport throughout the body: Nutrient transport is primarily carried out by the circulatory system (blood vessels), not the lymphatic system. The circulatory system transports nutrients, oxygen, and hormones to cells and removes waste products.
D) Waste removal through lymph nodes: The lymphatic system helps remove waste and toxins from the body by filtering lymph through lymph nodes, where harmful substances are trapped and destroyed by immune cells.
Therefore, the function NOT attributed to the lymphatic system is C) Nutrient transport throughout the body.
What is the process by which a fertilized egg implants itself in the lining of the uterus?
- A. Fertilization
- B. Implantation
- C. Gestation
- D. Parturition
Correct Answer: B
Rationale: Implantation is the correct answer. It is the process where a fertilized egg attaches itself to the lining of the uterus to establish a pregnancy. Fertilization is the initial step where the sperm and egg fuse to form a zygote. Gestation refers to the period of fetal development within the uterus. Parturition is the process of giving birth and is not related to the implantation of the fertilized egg, which occurs earlier in the reproductive process.
Which property of a substance refers to its ability to be stretched into thin wires?
- A. Conductivity
- B. Viscosity
- C. Ductility
- D. Malleability
Correct Answer: C
Rationale: Ductility is the property of a substance that allows it to be stretched into thin wires without breaking. It is a crucial property for materials used in wire production. Conductivity refers to the ability of a substance to conduct electricity or heat, not to be stretched into wires. Viscosity is the measure of a fluid's resistance to flow, not its ability to be stretched. Malleability is the property of a substance that allows it to be hammered or rolled into thin sheets, not stretched into wires.
What force keeps a car moving along a curved road?
- A. Gravitational force
- B. Normal force from the road
- C. Air resistance
- D. Friction between the tires and the road
Correct Answer: D
Rationale: The correct answer is D: Friction between the tires and the road. When a car travels along a curved road, the friction between the tires of the car and the road provides the necessary centripetal force required to keep the car moving in the curved path. This friction allows the tires to grip the road and prevent the car from sliding off the curve due to inertia or momentum. Choices A, B, and C are incorrect because gravitational force, normal force from the road, and air resistance do not play a significant role in keeping a car moving along a curved road. While these forces may have other effects on the car's motion, they are not the primary force responsible for maintaining the car's trajectory along a curve.
Which property of a substance remains constant regardless of changes in its shape or size?
- A. Mass
- B. Weight
- C. Volume
- D. Density
Correct Answer: A
Rationale: The correct answer is 'Mass.' Mass is a measure of the amount of matter in an object and remains constant regardless of changes in its shape or size. Weight, volume, and density can all change depending on the conditions, but mass remains the same. Weight is the force exerted on an object due to gravity, which can change based on the gravitational pull. Volume is the amount of space an object occupies, which can change if the shape or size of the object changes. Density is the mass of a substance per unit volume, which can change if either the mass or volume changes. Therefore, in this scenario, mass is the property that remains constant regardless of changes in shape or size.