hydrocracking: the process whereby hydrocarbon molecules of petroleum are broken down into kerosene and gasolene by the addition of hydrogen under high pressure in the presence of a catalyst
cracking: the process whereby heavy molecules of naphtha or petroleum are broken down into hydrocarbons of lower molecular weight (especially in the oil-refining process)
neoteny: an evolutionary trend to be born earlier so that development is cut off at an earlier stage and juvenile characteristics are retained in adults of the species