Minecraft has MOBs in it that you kill for food or resources.
This is the Minecraft cow. If you kill them they drop 0-2 leather and 1-3 beef.
This is the MInecraft pig. They drop 1-3 raw pork chops upon death.
This is the Minecraft chicken. It drops 1 raw chicken and 0-2 feathers when it dies. Also every 5-10 minutes it lays an egg.
This is a Minecraft sheep. It drops one wool upon death in its respective color. Also you can use shears to get 1-3 wool without killing it.