Life inside death (abiotic and biotic factors)

Had to draw something dad had abiotic and biotic factors (thing whit life and things without life). To be franc, I personally would not draw something similar again, don like skulls, sorry :l. But either way, also, first time I use color (prismacolor) in a project in Graphic Design, really like to use colors (even if it takes me the double of time to finish XP)