To change behavior or actions in response to outside conditions 5 letters

i dont know it at allnow im just getting points at this pint

bacteria could be both, harmful and to us. harmful bacteria could make us sick and probably even by getting the chances of getting a disease, but good bacteria fight it off with your immune system. there is always bacteria everywhere we go. we need to make sure to wash our hands after using the restroom, before eating, after eating, after petting an animal too. so you see, bacteria is everywhere and is harmful or . i hope this . : ) : ) : )

because it travels in smaller waves then all other colors, causing it to be the most visible color