<span>Exposure to mutagenic agents</span>
The answer is cerebellum. By processing and interpreting impulses from the motor cortex and brain stem nuclei as well as sensory pathways, the cerebellum provides the precise timing and appropriate patterns of skeletal muscle contraction for smooth coordinated movements and agility needed for daily living. It also plays a poorly understood role in cognition. Cerebellar activity occurs subconsciously (e are not aware of it).
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If A is dominant allele, and a is recessive allel, than:
p is frequency of A allele, q is a frequency of a allele, p2 is a frequency of homozygous dominant genotype, 2pq is frequency of heterozygous genotype and q2 is frequency of homozygous recessive genotype.
If the population is in Hardy-Weinberg equilibrium; p+q=1
p=0.15 q=1-0.15=0.85
2pq=2*0.15*0.85=0.255~26%
Good government, resources and trade with other places, and employment options.