The study is conducted to analyze the questioning styles in three middle school environmental textbooks in terms of frequency, type, and placement of questions. It is also to analyse and compare the kinds of scientific processes elicited by the questions in the topics of textbook. The instrument was the Textbook Questioning Strategies Assesment Instrument (TQSAI) which was developed the Cooperative Teacher Preparation Program, University of California. The mean number of questions per topic was 4.0 and the ratio of questions to sentences was 3.8%. The numbers of empirical and non-empirical questions were 52.5% and 47.5% for textbook D, 56.6% and 43.4% for textbook J, and 92.7% and 7.3% for textbook K, respectively. The open-hearted question was the highest in all types of questions for three middle school environmental textbooks. The explanatory question was the highest in all characteristics of questions. The types of various questions were distributed throughout textbooks including the green field, debate-discussion, examination, and so on.

In order to clarify the seasonal composition and abundance of zooplankton community in Macheon Bay. the study was carried out trimonthly during the period from April 1996 to January 1997. 37 taxa and 7 unconfirmed species of zooplankton was identified. It consisted of 28 species of Protozoa. 1 species of Cnidaria, 1 species of Annelida, 2 larva of Mollusca, 3 species of Rotifera, 4 species and 4 larva of Arthropoda and 1 larva of Echinodermata, respectively. Seasonal succession of the dominant species was Tintinnopsis beroidea in the spring. Copepodite in the summer. Tintinnopsis directa in the autumn and Ceratium fusus in the winter. Abundance of zooplankton ranged from 4.720 to 4 1.215 inds./ . It was high in the summer (4 1.215 inds./ ) and low in the spring (4.720 inds./ 1 ). Dominant index ranged from 0.133 (in the spring) to O. 551 (in the winter). Species diversity index ranged from 1.114 (in the winter) to 1.996 (in the spring).

We examined the genetic variation within the species, the patterns of genetic diversty between populations, thermostability variations of enzymes and temperature tolerances of Corbicula japonica from the two main rivers in Korea. Starch gel electrophoresis was used to examine the genetic variation of 22 loci. Heating experiments of electrophoresis under the condition of 40±5° for 15±5 min disclosed thermostability differences, called heat-sensitive and heat-resistant types, within each electrophoretic allozyme. Genetic diversity at the natural species level was high (77.3%), whereas the extent of heat-treat groups was relatively low (52.6%). The genetic diversity trends to decrease from the source of two main rivers (the Sumjin River and the Nam River) to the mouths. Based on the data available such as considerable high genetic diversity compared with a mean value of C. japonica species, It is recommended that several populations of the species in Korea should be preserved.