Free levelled English reading practice. Read for meaning first, then use the full Speed Reading tool to time yourself and track your progress.
The adult human brain weighs only about 1.3 to 1.4 kilograms, yet it coordinates perception, movement, memory, emotion, language and countless automatic processes that keep the body functioning. Its activity depends on networks containing roughly 86 billion neurons, together with enormous numbers of supporting glial cells. Neurons communicate through electrical and chemical signals, forming changing patterns of activity rather than operating as isolated switches. Different brain regions are specialised to some degree, but popular claims that a person is simply “left-brained” or “right-brained” greatly oversimplify how cognition works. Most complex tasks recruit distributed networks across both hemispheres. Another important property is neuroplasticity: the nervous system can change its connections and patterns of activity in response to experience, learning or injury. Plasticity is especially strong during development but continues throughout life. Sleep also plays a crucial role in brain function, contributing to memory, attention and metabolic housekeeping. Despite rapid advances in neuroscience, fundamental questions remain. Researchers can map activity associated with decisions or memories, but explaining how subjective conscious experience arises from physical processes remains profoundly difficult. The brain is therefore both a biological organ we increasingly understand and one of science's deepest unsolved problems.
Comprehension questions
Approximately how many neurons are in the human brain?
How do neurons communicate?
What does the passage say about left-brain/right-brain claims?
