When we think about stress, we usually paint it as a bad thing. But in reality it’s how we get along in the world. Our stress response helps us navigate an ever-changing environment—it’s the reason we’re able to react to new situations to figure out if they’re safe or dangerous. Without it, we wouldn’t survive. The same goes for plants, which are stressed by environmental changes that threaten their health, such as flood or drought, or by critters that would harm or kill them, like pathogens and plant-eating insects.