REM sleep is also called paradoxical sleep because in this state, the sleeper is difficult to wake-up in spite of showing the brain waves associated with waking, hence the term paradoxical, as the state itself is somewha... More »

Dogs dream during the REM phase of sleep, just like humans. There is evidence that they dream about their daily activities. They often twitch, vocalize and breathe differently while dreaming. More »

You do not swallow saliva in your sleep because facial muscles are relaxed. Most people wake up with saliva in their mouth, which is instantly swallowed once that person wakes up. While sleeping, people do produce saliva... More »

Most people can stop the problem of drooling in their sleep by changing their sleep position. Dr. Celite Kushida of the Stanford University Center for Human Sleep Research advises people with sleep-related drooling issue... More »

Humans need sleep because it is an essential process to maintain health. Sleep is necessary for cognitive functions, such as memory, emotions and learning, as well as physical functions, such as cardiovascular performanc... More »

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Environmental pressure is another term for natural selection, a process that encourages some genes to survive because they are conducive to the environment while others die. This process slowly causes a distinct species ... More »

Producer is a term used to refer to plants in science. Plants produce their own food using the energy of the sun, water and carbon dioxide in a process known as photosynthesis. This energy is eventually transferred to al... More »