Answer to Question 1
Answer: A synopsis (or abstract) is simply a brief overview of the report's most important points. An executive summary is a fully developed mini version of the report itself.
Executive summaries are often more detailed than synopses, including images and headings just as the actual report does.
Answer to Question 2
Answer: Prefatory parts are placed before the text of your report. However, many of these parts (such as the table of contents, list of illustrations, and executive summary) are easier to prepare after you've written the report because they are based on the main text. Other parts (such as the cover and title page) can be prepared at almost any time.
Difference between....
Summary of Isomerism
Summary of Antidiabetic Drug Classes
Summary of T-Cell Types
Summary of Drug Action: Common Routes of Administration
Summary of the Structures of the Eyeball