The answer may be, Replication, but I am unsure.
Answer: Selective breeding
Explanation:
Selective breeding or artificial breeding is a process that allows humans to select parents in plants and animals that have desirable traits. Such parents are bred to produce offspring that have desirable traits from both parents. Humans have bred many species of plants and animals to improve the quality of plant and animal yields in terms of crops, milk, meat, eggs, and other derivatives.
Because they don't have a or any cells and have no DNA
During the initial exposure to the allergen, contact is made with B cells, these B cells differentiate and produce IgE antibody. The IgE antibodies which works against the allergens are released into the blood stream where they binds to Fc receptors which are located on mast cells and basophils. Now, the mast cells has become sensitized and they will wait patiently for the second exposure. When contact with the allergen is made the second time, the allergen becomes attached to the IgE present on the mast cells and this result in degranulation which trigger a lot of allergic responses.