Exoplanets Without Lots of Water Can't Maintain Their Carbon Cycles

Water is critical to life because cells need liquid to function. That's why scientists focus on finding and studying exoplanets in habitable zones. But even if they're in habitable zones, exoplanets need lots of water to support their carbon cycles. So without water, exoplanets become inhospitable greenhouse planets, regardless if they're in habitable zones or not.