Documenting demographic trends help please!?

[Jeff]

I am currently doing a distance correspondence course, and I have to take a marketing course in order to get my diploma down the road. I was mainly just looking for a second opinion on this assignment that I am required to do. The last part of this assignment asks me to, document demographic trends (eg. aging population, erosion in spending power. etc.) and relate these products you have chosen to report on. So basically for the first half of the assignment I had to do an environmental scan of 2 products of my choice being, iPhones and Facebook. So this last part I was just hoping that someone could give me their take on what they think this last part of the assignment is all about? Thank you very much to anyone that can lend a hand.