Combing the 4 topics into one

Book
Schaie, K. W., & Willis, S. L. (Eds.). (2016). Handbook of the psychology of aging (8th ed.). San Diego, CA: Elsevier.
Assignment
You must read Chapters 17, 18, 19, & 20 and do a Synthesis paper on those 4 chapters. The paper should provide single, complete, and UNIFYING thought/idea (i.e., a synthesis) about the readings that goes beyond the material. The 4 chapters must be unified as one. This paper is not a summary of the chapters. This is a Synthesis Paper not a summary of the chapters. The 4 chapters must be unified in a nutshell as one.
Must have 3 subtitles to reflect the 4 chapters read.
*Please make sure it is 0% plagiarism. Thank you