Nokea
What is the myelin sheath and what does it do?
- A. A group of nerve cells that perform a specific function.
- B. A fatty substance that insulates some nerve fibers.
- C. A fluid-filled cavity within the brain.
- D. The junction between two neurons.
Correct Answer: B
Rationale: The myelin sheath is a fatty substance that insulates some nerve fibers. It is made up of specialized cells that wrap around the axons of neurons, providing insulation and speeding up the transmission of nerve impulses. Choice A is incorrect as the myelin sheath is not a group of nerve cells but rather a substance that surrounds nerve fibers. Choice C is incorrect as the myelin sheath is not a fluid-filled cavity within the brain. Choice D is incorrect as the myelin sheath is not the junction between two neurons.
You may also like to solve these questions
In the cardiovascular system, what does the term 'double circulation' refer to?
- A. The separation of oxygenated and deoxygenated blood flow within the heart.
- B. The regulation of blood pressure through vasoconstriction and vasodilation.
- C. The cyclic contraction and relaxation of the heart muscle.
- D. The existence of two separate circulatory pathways, one for the lungs and one for the body.
Correct Answer: D
Rationale: The term 'double circulation' in the cardiovascular system refers to the existence of two separate circulatory pathways, one for the lungs (pulmonary circulation) and one for the body (systemic circulation). Oxygen-poor blood is pumped from the heart to the lungs for oxygenation, and then oxygen-rich blood is pumped from the lungs back to the heart to be circulated to the rest of the body. Choices A, B, and C are incorrect as they do not accurately describe the concept of 'double circulation.' Choice A refers to the separation of oxygenated and deoxygenated blood within the heart, choice B relates to blood pressure regulation mechanisms, and choice C describes the cardiac muscle's contraction and relaxation, none of which define 'double circulation' in the context of the cardiovascular system.
A car skids on a wet road. What is the main force preventing the car from stopping?
- A. Friction
- B. Gravitational force
- C. Normal force from the road
- D. Air resistance
Correct Answer: A
Rationale: The correct answer is A: Friction. Friction is the force that opposes the motion of the car on the wet road surface, making it harder for the car to stop. When the car skids, the friction between the tires and the wet road surface is reduced, leading to a loss of traction and making it challenging for the car to come to a halt. Gravitational force (choice B) is the force that pulls objects toward each other due to gravity and does not directly impact the car's ability to stop on a wet road. The normal force from the road (choice C) is the force exerted by the road surface perpendicular to the car's tires and does not play a significant role in stopping the car. Air resistance (choice D) is the force that opposes the motion of an object through the air, but it is not the main force preventing the car from stopping on a wet road.
Which of the following is NOT a common symptom of lactose intolerance?
- A. Gas
- B. Bloating
- C. Diarrhea
- D. Nausea
Correct Answer: D
Rationale: A) Gas: Gas is a common symptom of lactose intolerance. When lactose is not properly digested, it can ferment in the colon, leading to the production of gas.
B) Bloating: Bloating is another common symptom of lactose intolerance. The buildup of gas in the digestive system can cause bloating and discomfort.
C) Diarrhea: Diarrhea is a common symptom of lactose intolerance. When lactose is not broken down in the small intestine, it can draw excess water into the colon, resulting in diarrhea.
D) Nausea: Nausea is not a common symptom of lactose intolerance. While some individuals may experience mild stomach discomfort or cramps, nausea is not typically associated with lactose intolerance.
What is the scientific term for the monthly cycle in females that prepares the body for potential pregnancy?
- A. Ovulation cycle
- B. Menstrual cycle
- C. Implantation cycle
- D. Gestation cycle
Correct Answer: B
Rationale: The correct answer is B: Menstrual cycle. The menstrual cycle is the scientific term for the monthly cycle in females that prepares the body for potential pregnancy. This cycle involves various phases, including the release of an egg from the ovary (ovulation), thickening of the uterine lining in preparation for a fertilized egg, and shedding of the uterine lining if pregnancy does not occur (menstruation). Choices A, C, and D are incorrect. Option A, Ovulation cycle, only refers to the specific phase of egg release from the ovary. Option C, Implantation cycle, pertains to the process of the fertilized egg attaching to the uterine wall. Option D, Gestation cycle, denotes the period of fetal development during pregnancy, which is distinct from the monthly cycle preparing the body for potential pregnancy.
What is the term for the reaction between an acid and a base to produce water and a salt?
- A. Combustion
- B. Neutralization
- C. Oxidation
- D. Decomposition
Correct Answer: B
Rationale: Neutralization is the correct term for the reaction between an acid and a base to produce water and a salt. During neutralization, the hydrogen ions from the acid react with the hydroxide ions from the base to form water, and the remaining ions combine to form a salt. Combustion involves a reaction with oxygen, oxidation is the loss of electrons, and decomposition is the breakdown of a compound into simpler substances. These processes do not accurately describe the reaction between an acid and a base to produce water and a salt.