The Institutional changes between the 1960s and 1980s shifted the public policy from emphasizing public interest to upholding and satisfying the regulations. Among the greatly affected was the educational system. The structures of the different learning institutions were changed to accommodate dynamic market models and work around the expected outcomes of learning.
<em>the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.</em>
The variable is the group that was given caffine, because thats what the doctors manipulated. They possibly altered the natural memory of the participants by giving them caffine. A more specific variable could be how much caffine each participant is given and what time are they given it.
I don't see the picture so i can't answer your question