Alright, now that both of my babies have germinated lets discuss how they got to where they are to this point. My babies first started as seeds so lets discuss that topic.

In the plants' infancy they looked like this

The embryo is the actual seed before it develops and takes root into the soil. 
The cotyledon is by definition "an embryonic in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed." So hear the cotyledon is obviously in a pre-mature stage but it will develop into the initial leaves of the plant. It is present in both mono and dicot seeds.
The endosperm by definition is "the part of a seed that acts as food store for the developing plant embryo." The endosperm usually contains starch along with protein and other nutrients to promote growth of the plant.
The epicotyl is by definition "the region of an embryo or seedling stem above the cotyledon." In plain terms it is the stem segment above the cotyledon. It is what drives the elongation and vertical growth of the plant.It is present in both mono and dicot seeds.
The radicle is the part of the seed that develops into roots.
The hypocotyl is what will develop into the part of the root directly beneath the cotyledon.
above image from here