Genetic variation is stored in a populationâs gene poolâthe combined. alleles of all of the individuals in a population. Different combinations of. alleles in a gene pool can be formed when organisms mate and have offspring. Each allele exists at a certain rate, or frequency.
Also found in: Wikipedia. cosÂ·tal surÂ·face. the surface of certain structures that face the ribs; they are the costal surfaces of the lungs (facies costalis pulmonis [TA]) and the scapula (facies costalis scapulae [TA]).
Lining the surface of the stomach are tall columnar surface mucus cells. These cells have mucin granules and extend into the gastric pit. These cells contain mucin granules in their apical cytoplasm that is released to provide a protective coat over the surface of the stomach.ining the surface of the stomach are tall columnar surface mucus cells. These cells have mucin granules and extend into the gastric pit. These cells contain mucin granules in their apical cytoplasm that is released to provide a protective coat over the surface of the stomach.