What is the name given to any object or change in the environment that affects the external or internal state of an organism?

If bacteria are much too small to see, what is one reason why can we see colonies in the petri dishes that have plenty of food to eat after only a few days?

When is your respiration rate likely to change? a. when your intestines are digesting b. when your cells have too much glucose c. when your cells need more oxygen d. when your liver is working after a meal

Which of the following best describes the relationship between glucose and complex molecules such as hormones?