Answer:
The action or process of accumulating, state of being or having accumulated, a collecting together. Repeated exposures to a chemical or drug may result in the progressive increase of its concentration in an organism, organ or tissue.
Explanation:
collecting
basically the accumulation of elements and compounds of harmful substances in the tissues of living organisms
Cytosine
Purine, Adenine, and Guanine are all purines
not sure if this is what you need.
