If plants need to take in carbon dioxide why don't they keep their stomata open all the time?

Plants don't keep their stomata open all the time to prevent excessive water loss through transpiration. While stomata facilitate the uptake of carbon dioxide for photosynthesis, open stomata also allow water vapor to escape. By regulating stomatal opening, plants balance the need for CO2 intake with the need to conserve water, especially in dry or hot conditions. This regulation is crucial for their survival and overall health.