Scientific Research
Dandelions can be very important to a garden ecosystem as well as to human health. Dandelions attract important ladybugs and provide early spring pollen for their food. Dandelions long roots aerate the soil and enable the plant to accumulate minerals which are added to the soil when the plant dies.

Relevance
This photo shows two dandelions next to each other in a mist of grass and clovers. It is relevant because the dandelions help pollinate the soil and gives it nutrients.

Other Comments
The information I got I got from http://www.pesticide.org/dandelions.html

I took this photo on my cell phone when I was walking down the street.