Hey there!
There are different types of nerves. Some of them are sensory nerves like the ones in your hands and feet, and some complete other functions. However, they all originate from somewhere.
Cranial nerves originate from the brain itself, and spinal nerves come from the spinal cord. Damaging any can cause serious injury like death and paralysis. There are 12 cranial nerves in the nervous system, and 10 out of 12 originate in the brain stem.
Hope this helps!
Unlike natural selection, genetic drift does not depend on an allele’s beneficial or harmful effects. Instead, drift changes allele frequencies purely by chance, as random subsets of individuals (and the gametes of those individuals) are sampled to produce the next generation.
Every population experiences genetic drift, but small populations feel its effects more strongly. Genetic drift does not take into account an allele’s adaptive value to a population, and it may result in loss of a beneficial allele or fixation (rise to 100\%100%100, percent frequency) of a harmful allele in a population.
The founder effect and the bottleneck effect are cases in which a small population is formed from a larger population. These “sampled” populations often do not represent the genetic diversity of the original population, and their small size means they may experience strong drift for generations.
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The particles that cause the aurora are energized in the magnetosphere, that is, above the atmosphere. If they don't reach 10,000 volts, they will still cause auroral light. The lower energy won't change the wave length of the light, but will cause the light to be dimmer.
Explanation: