Chemical fossils (e.g. alkanes and porphyrins) are often the only evidence for life in rocks of PRECAMBRIAN age.
Chemical fossils (e.g. alkanes and porphyrins) are often the only evidence for life in rocks of PRECAMBRIAN age.
化学化石（烷烃和卟啉）是前寒武纪地层中生命存在的唯一证据。