Passage 121
Each night we alternate between two kinds of sleep; active sleep and passive sleep// Passive sleep, gives our body the et that is needed, and prepares us for active sleep, in which dreaming occurs.// In passive sleep, the body is at rest, the heartbeat slows down and the body processes become very slow.// This stage of sleep is known as slow wave sleep because the brain waves move in a very slow, regular rhythm.//
Passage 122
From recorded time, man has been fascinated with music and the hardware of sound reproduction.// The modern recording industry was born to satisfy an enormous market for all types of music; folk, classical, orchestral and popular.// The widespread use of electricity led to the invention of the portable record player, while the rise of the electronic industry fed the growing demand for hi-fi stereo systems.// It is certain that the ever-improving technology will give rise to another development beyond digital sound, making the CD obsolete from general use.//
Passage 123
Every living thing is a unique combination of the tiny pieces of matter called genes that carry information from parents to offspring.// Our genes decide what we are, what we look like, how long we live and so on.// There are people who are obsessed with cloning (克隆) experiments and wish to apply the theory of genetical replication to cloning human beings.// The idea of combining animal genes with plant genes, or animal genes with human genes has upset many people for ethical reasons.//
Passage 124
The human brain contains an average of ten billion neurons, or never cells, each of which in linked with one thousand to ten thousand other neurons.// These nerve cells participate in countless electrical microcircuits, which makes possible though, perception, communication, and other types of mental activity. // In the cortex of the brain reside human cognitive abilities such as sophisticated reasoning, linguistic skills and musical ability.// The cortex, which is not present to a comparable degree in any other species, represents man’s relatively recent evolutionary step in neurological development.//
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