During which stage of human development is it most likely that life changes will require emotional and social adjustments?

The answer is "Older adulthood". 

The hypothesis depicts eight phases through which a healthy human should go from early stages to late adulthood. In each stage the individual goes up against, and ideally completes, new difficulties. Each stage expands on the fruitful fulfillment of prior stages. The difficulties of stages not effectively finished might be required to return as issues later on.

i honestly have no idea