4.1 WHY WOMEN LIVE LONGER Some British scientists now believe that women live longer than men (a) T cells, a vital part of the immune system that protects the body from diseases. Previously, various theories have attempted to explain longer female life expectancy. Biologists claimed that women lived longer (b) they need to bring up children. Others argued that men they die earlier. But a team from Imperial women having take more risks, (c)_ College think that the difference may be (d)_ better immune systems. Having studied a group of men and women they found that the body produces fewer T cells as it gets older, (e)_ ageing process. However, they admit that this may not be the only factor, and another research project may be conducted. (f)_ the