You Are Waiting at the Crosswalk for the Light to Change

question 260

Multiple Choice

You are waiting at the crosswalk for the light to change. Finally the "WALK" sign illuminates and you begin to cross the street. Even though you watch for traffic as you cross, you have learned that the appearance of this light usually means that it is safe to cross the street. Thus, the "WALK" sign would be considered an example of a:

• A) positive reinforcer.
• B) negative reinforcer.
• C) discriminative stimulus.
• D) response cost.

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Definitions:

ATP

ATP, or adenosine triphosphate, serves as the primary energy carrier molecule in cellular metabolic activities.

Calvin Cycle

Cyclic series of reactions in the chloroplast stroma in photosynthesis; fixes carbon dioxide and produces carbohydrate. See C3 Plant.

Ribulose Bisphosphate

A five-carbon sugar to which atmospheric carbon dioxide is bound during the first major step of carbon fixation in photosynthesis.

PGA Molecules

Short for phosphoglyceric acid, involved in the biochemical process of photosynthesis and glycolysis.