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.  

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

explanation:

digestion

it excretes wastes