The answer is pancreas. The pancreas is a gland which is then in the abdomen. It is a flat shape and an accessory organ that neutralize the stomach acid through it's secretions before it then would reach in the intestines.
The accessory organ that has secretions that can neutralize
stomach acid before it reaches the intestines is the pancreas. The pancreas
produces and secretes sodium bicarbonate, which can protect intestines by
neutralizing stomach acid. This may also relieve symptoms of acid reflux
temporarily.
Genetic drift is change in allele frequencies in a population from generation to generation that occurs due to chance events
The genetic drift occurs due to random fluctuation of any allele in a gene pool and is more efficient in small population
The founder effect and the bottleneck effect are cases in which a small population is formed from a larger population which means they may experience strong drift for generations
In founder effect a genotype from a homogeneous gene pool migrate to a newer habitat and colonize there and form a newer community which leads to the genetic drift to the original population, speciation which occurs in this effect is the peripatric speciation
In bottleneck effect the elimination of inferior genotype from a homogeneous gene pool occurs due to the strong selection pressure and changing environmental conditions which leads to genetic drift and a only a few most adapted genotype survives and flourish
Natural Selection
Natural selection is a selection pressure which operates in a population and allow the best fitted genotype to survive in changing environmental conditions and eliminate the other genotype which are not fit
Genetic drift, mutation and sexual selection are important causes of natural selection
Directional natural selection favours the superior genotype and eliminate the inferior and intermediate genotype, in the history of evolution the most common natural selection is directional natural selection
Stabilizing natural selectionfavours the intermediate genotype but eliminates the extreme genotype
Bidirectional natural selection favours the extreme genotypes but eliminate the intermediate genotypes
