Which country's government earns 33% of its budget from oil sales A. Mexico. B. Brazil C.Cuba 

The correct answer is letter A

The work Burrhus Frederic Skinner is the most celebrated expression of behaviorism - current that dominated the thought and practice of psychology, in schools and offices, until the 1950s. Behaviorism restricts its study to behavior (behavior, in English), taken as a set of reactions by organisms to external stimuli. The principle of behaviorism is that it is only possible to theorize and act on what is scientifically observable.

Skinner's theory is based on the idea that learning occurs due to changes in manifest behavior. Changes in behavior are the result of an individual response to events (stimuli) that occur in the environment. Thus, a response produces a consequence. When a particular Stimulus-Response (S-R) pattern is reinforced (rewarded), the individual is conditioned to react. The characteristic that distinguishes operant conditioning from previous forms of behaviorism is that the organism can emit responses, instead of obtaining responses only due to an external stimulus.

Reinforcement is the key element in Skinner's S-R theory. A reinforcement is anything that strengthens the desired response. It can be a verbal compliment, a good grade, or a feeling of accomplishment or increased satisfaction. The theory also covers negative reinforcements - an action that prevents an unwanted consequence.