Booker has a really bad headache, so he takes a new painkiller. the drug works wonderfully to relieve his headache. the next time booker has a headache, he definitely will take that drug. booker's behavior of taking the new drug has been:

The correct answer is positively reinforced.  

The positive reinforcement in an operant conditioning incorporates the supplementation of a reinforcing stimulus following a behavior, which makes it more probable that the behavior will take place again in the coming time.  

When a favorable reward, outcome, or an incident takes place after an action, then that specific behavior or response will get strengthened.  

1 digestive system

2 stomach

3 bladder

4 carbon deoxide

5 tiger

if your own plato the answer is b. the fern transitioned from sporophyte generation to gametophyte generation.