“Within ten years - the JWST will find evidence of photosynthezing life on an exoplanet.”

There are currently 5,742 confirmed exoplanets, in 4,237 star systems. Some of them are rocky, approximately-Earth-sized planets, within their stars' potential habitability zones. The JWST is the first technology that we have had, that is at all capable of analyzing the atmospheres of exoplanets. That is one of its many missions. It has already begun doing so. A significant amount of free oxygen, O₂, in any planet's atmosphere - would a certain sign of phyosynthesizing life. Other signs are also being looked for.