I’m working on a psychology discussion question and need an explanation and answer to help me learn.

Late adulthood spans the time when we reach our mid-sixties until death. This is the longest developmental stage across the lifespan. In this chapter, we will consider the growth in numbers for those in late adulthood, how that number is expected to change in the future, and the implications this will bring to both the United States and worldwide. 

Late adulthood is the fastest growing age division of the United States population. Currently, one in seven Americans is 65 years of age or older. By the year 2050, almost one in four Americans will be over 65, and will be expected to live longer than previous generations. This increasingly aged population has been referred to as the “Graying of America”.

Answer & responding to the following prompt(s) below: 

1. What are the different theories of aging (name 2)? What do they argue? What do you see as the societal implications regarding our aging population? Which resources should we make sure are in place to serve our (growing) elderly population?
2. What happens in Parkinson’s disease? Who does it affect? Describe 2 physical or functional changes in the brain during late aduldhood. What are they? How do they affect the individual? 

Link to textbook, here: https://www.merlot.org/merlot/viewMaterial.htm?id=773310795