Here are some examples:
* Bacteria: Some bacteria can divide every 20 minutes, so in that sense, their "lifespan" is very short. However, they don't really "die" in the way multicellular organisms do. They just divide and create new cells.
* Mayflies: Some mayfly species have an adult lifespan of only a few hours, dedicated solely to reproduction.
* Fruit flies: These insects have an average lifespan of around 30 days.
* Water fleas: Some species of water fleas live for only a few days.
It's difficult to say definitively which organism has the shortest lifespan, as it depends on the specific species and environmental conditions. However, the contenders for the shortest lifespans are generally small, fast-growing organisms that reproduce quickly.
