tion 1974-80 of the Academy of Sclences.of Cuba, was an essential antecedent to the national structuring of research and development In terms of problems and themes. <•> 1 Cuban peso= 1,17 US$ at the offlcal rate of exchange of the Banco Naclonal de Cuba during the first half of 1963 The Five-Year Plan 1981-85 was elaborated starting from the~ experience obtained In planning, management and control 9f the scientific and technological activities of the previous quinquen­ nium. For this period, the scientific and technological research problems were classified according to Its level of approval In two categories: Main Problems and Branch Problems. Main Problems must be related to the objectives of the stra­ tegy of scientific and technological development of the country; they tackle Integral solutions which generally require the parti­ cipation of more than one organization In Its fulfillment and as such they demand a differentiated attention by the Academy of Sciences of Cuba In their fulfillment and control. according to effective regulations. Branch Problems Integrate the research approved by the orga­ nizations corresponding to their branch development and the needs of production or services In each branch. They emphasize those . research areas which would contribute to exports development and Imports substitution; to quality Improvement; to the Increase of productivity; and to cost reductions. According to their characteristics and objectives, Main Problems are classified Into four groups: State Main Problems Medicine Main Problems Social Sciences Main Problems Beste Research Main Problems In order to guarantee the eppropriate Interrelations among different factors which participate In the planning and control of these Main Problems. a Problem Commission Is created for eoch of them. It Is formed as a consultative scientific and technological collective body charged with the Integral assessment of the deve­
**Analysis**
The text appears to be discussing the planning and organization of scientific and technological research in Cuba, with a focus on the national strategy for development. It mentions the classification of research problems into "Main Problems" and "Branch Problems", and the creation of problem commissions to oversee their implementation. This suggests that the text is primarily concerned with the development of science and technology in Cuba.

**Category**
Science and technology, Economic development