The following text is from a neuroscience article.
The human brain consumes approximately 20% of the body's energy despite comprising only 2% of body weight. This disproportionate energy use supports the billions of synaptic connections underlying thought and consciousness. Sleep allows metabolic waste products to be cleared from neural tissue. Chronic sleep deprivation may accelerate cognitive decline by impeding this essential maintenance function.
What is the primary purpose of the text?
To argue that people should sleep more than eight hours daily
To explain the brain's energy requirements and the role of sleep
To compare brain function across different age groups
To provide tips for improving concentration and focus
Correct Answer: B
Choice B is the best answer. The text explains energy requirements (20% consumption) and sleep's role (clearing waste, preventing decline).
- Evidence: The text notes energy use: "consumes approximately 20% of the body's energy." It explains sleep's role: "allows metabolic waste products to be cleared," "essential maintenance function."
- Reasoning: The passage connects the brain's high energy needs to the necessity of sleep for maintenance.
- Conclusion: The purpose is to explain requirements and sleep's role.
💡 Strategy: Summarize: Brain needs energy + Sleep cleans up the mess.
Choice A is incorrect because specific sleep duration isn't advocated. Choice C is incorrect because age groups aren't compared. Choice D is incorrect because concentration tips aren't provided.