The notion of change is an important part of the definition of learning, because something must be different about an organism after learning hast taken place. The change in behaviour may be immediate (for example, changing a tennis serve immediately after a coach suggests a way to improve it), or the change may be delayed and actually occur sometime after learning as taken place (for example, changing a tennis serve the next time you play tennis after watching an instructional video. Furthermore, the change may be possible but not evident because of a lack of opportunity. (For example, by watching Roger Federer in a tournament you know how to improve your tennis serve but you never play tennis). Consequently, learning refers to the potential to behave in a particular way, as well as behaviour that is observed to take place.
^^I typed out the part i had trouble with. Can someone explain the parts i've highlited?