Answer:
Until recently, most neuroscientists thought we were born with all the neurons we were ever going to have. As children we might produce some new neurons to help build the pathways - called neural circuits - that act as information highways between different areas of the brain. But scientists believed that once a neural circuit was in place, adding any new neurons would disrupt the flow of information and disable the brain’s communication system.
In 1962, scientist Joseph Altman challenged this belief when he saw evidence of neurogenesis (the birth of neurons) in a region of the adult rat brain called the hippocampus. He later reported that newborn neurons migrated from their birthplace in the hippocampus to other parts of the brain. In 1979, another scientist, Michael Kaplan, confirmed Altman’s findings in the rat brain, and in 1983 he found neural precursor cells in the forebrain of an adult monkey.
These discoveries about neurogenesis in the adult brain were surprising to other researchers who didn’t think they could be true in humans. But in the early 1980s, a scientist trying to understand how birds learn to sing suggested that neuroscientists look again at neurogenesis in the adult brain and begin to see how it might make sense. In a series of experiments, Fernando Nottebohm and his research team showed that the numbers of neurons in the forebrains of male canaries dramatically increased during the mating season. This was the same time in which the birds had to learn new songs to attract females.
Why did these bird brains add neurons at such a critical time in learning? Nottebohm believed it was because fresh neurons helped store new song patterns within the neural circuits of the forebrain, the area of the brain that controls complex behaviors. These new neurons made learning possible. If birds made new neurons to help them remember and learn, Nottebohm thought the brains of mammals might too.
Other scientists believed these findings could not apply to mammals, but Elizabeth Gould later found evidence of newborn neurons in a distinct area of the brain in monkeys, and Fred Gage and Peter Eriksson showed that the adult human brain produced new neurons in a similar area.
For some neuroscientists, neurogenesis in the adult brain is still an unproven theory. But others think the evidence offers intriguing possibilities about the role of adult-generated neurons in learning and memory.
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Answer:
These big and hefty mountain ranges are play important role in weather and wind patterns in their related geographical region. Mountain ranges such as Himalayas, Rockies and Alps affects the weather and movement of wind on global level as well.
In absence of these mountains the global pattern of the wind can be affected and cause drastic change in global climate change as they play crucial role as barrier to wind and jet streams by diverting or dividing it.
For instance Himalayas, during the northern winters diverts the wind and acts as barrier for wind which prevents it from freezing. Rockies and Andies blocks the moisture laden winds flow from Pacific Ocean to western flanks of the american continent that leads to a dry region called rain Shadow desert zone.
Hence if these mountain ranges are gone these impacts will not be felt. Similarly Himalayas in India, cause monsoon wind to strike and cause rain in the region. So winds are greatly affected by these Mountains. If these mountain ranges were gone, winds will flow undisturbed as there would be no barrier to global wind patterns.
Answer:
B. Sequence of nucleotides in the organism's DNA
Explanation:
The genes within an organism rely on the DNA within those organisms. Different DNA create different genes.
Answer: Electromagnetism
Explanation: Electromagnetism is one of the four fundamental forces (the other three are gravity, strong nuclear force and weak nuclear force.) It acts between all the particles having an electrical charge.
The answer to this question would be: parasympathetic division
Parasympathetic nervous is part of the autonomous nervous system. In the autonomous nervous system, the sympathetic system is used when you enter the "fight or flight" mode. In this case, the body will be prepared to be able to take a decision as quickly as possible in a strenuous state. The nervous also cause an increase in the heart and breathing rate to increase body capability.
Parasympathetic is the opposite of it which was activated to calm the body so it can maintain the normal body function.
