The process by which a cell in culture acquires the ability to divide indefinitely, similar to the division of cancer cells ; or a change in genotype and phenotype due to the assimilation of external DNA by a cell . When the external DNA is from a member of a different species, transformation results in horizontal gene transfer:

The correct answer to fill in the blank is: transformation.

Explanation:

Transformation is a process that happens to a) cells when they change their phenotypes due to new genetic material, or b) cultured cells that keep having spontaneous phenotypic alterations due to the changes in their DNA.

Transformation can occur because spontaneously, or because of an infection with a transforming virus, gene transfection, exposure to chemical carcinogens or exposure to ionizing radiations.

frogs. the lower the ph the higher the acid content. frogs have the highest tolerance in this scenario.