The passage is about gerontogens. The writer says a cause of gerontogent is from gene 25% another from arsenic in groundwater,benzene in industrail emissions, ultraviolet radiation in sunlight, chemotherapy, anti HIV drugs, the toxic chemical in cigarettes and consuming too many calories. Sharpness's team has focus on one particular aspect of aging -a process called senescence , in which cells permanently stop dividing-p16. And the scientists are using their mice to tast potential gerontogens. The team has developed a strain of mice that produce a protein that glows whenever they do, p16 has a large number of cells that are damaged, they glow like crazy to say that when you give them to gerontogen. They sent animals to about 50 different laboratories to do the same. Thay're also working with a company called diagnostic tests p16 healthspen to create version of their biological age can be measured in person