Biotic or Not?

Biotic 

• tree
• leaves on tree
• fallen tree
• leaves on the ground
• twigs
• grass
• poison ivy
• other foliage
• ants
• birds
• mosquitoes
• wood pilings (on railroad tracks)
• me

Abiotic

• railroad tracks (steel)
• pebbles
• boulder
• trash
• dirt
• temperature
• my clothes