Adapted from Understanding Sleep
National Institutes of Health

Until the 1950s, most people thought of sleep as a passive, dormant part of our daily lives. We now know that our brains are very active during sleep. Moreover, sleep affects our daily functioning and our physical and mental health in many ways that we are just beginning to understand.
Nerve-signaling chemicals called neurotransmitters control whether we are asleep or awake by acting on different groups of nerve cells, or neurons, in the brain. Neurons in the brainstem, which connects the brain with the spinal cord, produce neurotransmitters such as serotonin and norepinephrine that keep some parts of the brain active while we are awake. Other neurons at the base of the brain begin signaling when we fall asleep. These neurons appear to "switch off" the signals that keep us awake. Research also suggests that a chemical called adenosine builds up in our blood while we are awake and causes drowsiness. This chemical gradually breaks down while we sleep.
During sleep, we usually pass through five phases of sleep: stages 1, 2, 3, 4, and REM (rapid eye movement) sleep. These stages progress in a cycle from stage 1 to REM sleep, then the cycle starts over again with stage 1. . . .
During stage 1, which is light sleep, we drift in and out of sleep. Our eyes move very slowly and muscle activity slows. People awakened from stage 1 sleep often remember fragmented visual images. Many also experience sudden muscle contractions called hypnic myoclonia, often preceded by a sensation of starting to fall. These sudden movements are similar to the "jump" we make when startled. When we enter stage 2 sleep, our eye movements stop and our brain waves (fluctuations of electrical activity that can be measured by electrodes) become slower, with occasional bursts of rapid waves called sleep spindles. In stage 3, extremely slow brain waves called delta waves begin to appear, interspersed with smaller, faster waves. By stage 4, the brain produces delta waves almost exclusively. It is very difficult to wake someone during stages 3 and 4, which together are called deep sleep. There is no eye movement or muscle activity. . . .
Sleep research is expanding and attracting more and more attention from scientists. Researchers now know that sleep is an active and dynamic state that greatly influences our waking hours, and they realize that we must understand sleep to fully understand the brain. Innovative techniques, such as brain imaging, can now help researchers understand how different brain regions function during sleep and how different activities and disorders affect sleep. Understanding the factors that affect sleep in health and disease may also lead to revolutionary new therapies for sleep disorders and to ways of overcoming jet lag and the problems associated with shift work. We can expect these and many other benefits from research that will allow us to more fully understand the impact of sleep on our lives.
3
Select the correct answer.
How does the last paragraph contribute to the development of the ideas in the passage?
A.
It discusses the various kinds of sleep disorders and how they can be prevented.
B.
It reinforces the idea that the body needs adequate sleep to function efficiently.
C.
It establishes the importance of researching the impact of sleep on a person's health.
D.
It explains the various kinds of studies that were conducted about sleep in the past.

that's a lot of reading foo

explanation:

yes as the core issue is an ever increasing majority of human workers   will become permanently unemployed as ever cheaper ever more intelligent automated machines inevitably replace more expensive human workers with each passing year.

economic growth now and in the future requires that fewer jobs are created for human workers. this is the desirable inevitable consequence. the automation of the jobs of human workers is the most profitable economically productive activity on the planet.

so as a global society we need to have a plan to deal with this inevitable change.

automation has been, is and will always be a friend to human society if human society on a global basis is prepared to deal with the inevitable consequences.

what is key is that automation killing all jobs is only a matter of when not if.

the real question is can we get past the now invalid assumption that most humans can work for a decent wage going forward.

i spent my working career increasing automation and increasing efficiency. this consequently reduces the hours worked by humans while increasing the output economic goods and services at an ever decreasing price.

why not have ever cheaper ever more intelligent automated machines create the vast majority of required economic goods and services as opposed to human workers?

why not have most human workers working less and retiring earlier?

there is much more to life than working forever.

fortunately, automation has been going on for decades and will continue as an irreversible process as ever cheaper ever more intelligent automated machines permanently replace more costly human workers.

i write this answer for the people that have an open mind and are not living in the past this is what i feel most effectively deals with the tractable issues that automation creates.

the question at hand is how we deal with automation going forward as a society.

automation is only a threat because society has yet to acknowledge automation is happening let alone effectively a having a plan to address it.

a conservative libertarian free market idea where individuals choose what economic goods and services are produced in the free market as the free market supply will respond to free market demand. this is not a centrally planned communist economy.

it is yes as the core issue is an ever increasing majority of human workers   will become permanently unemployed as ever cheaper ever more intelligent automated machines inevitably replace more expensive human workers with each passing year.

economic growth now and in the future requires that fewer jobs are created for human workers. this is the desirable inevitable consequence. the automation of the jobs of human workers is the most profitable economically productive activity on the planet.

so as a global society we need to have a plan to deal with this inevitable change.

automation has been, is and will always be a friend to human society if human society on a global basis is prepared to deal with the inevitable consequences.

what is key is that automation killing all jobs is only a matter of when not if.

the real question is can we get past the now invalid assumption that most humans can work for a decent wage going forward.

i spent my working career increasing automation and increasing efficiency. this consequently reduces the hours worked by humans while increasing the output economic goods and services at an ever decreasing price.

why not have ever cheaper ever more intelligent automated machines create the vast majority of required economic goods and services as opposed to human workers?

why not have most human workers working less and retiring earlier?

there is much more to life than working forever.

fortunately, automation has been going on for decades and will continue as an irreversible process as ever cheaper ever more intelligent automated machines permanently replace more costly human workers.

i write this answer for the people that have an open mind and are not living in the past this is what i feel most effectively deals with the tractable issues that automation creates.

the question at hand is how we deal with automation going forward as a society.

automation is only a threat because society has yet to acknowledge automation is happening let alone effectively a having a plan to address it.

a conservative libertarian free market idea where individuals choose what economic goods and services are produced in the free market as the free market supply will respond to free market demand. this is not a centrally planned communist economy.

hope this