Answer:
Step 1: A tree absorbs the carbon from the atmosphere into its leaves for photosynthesis.
Step 2: A caterpillar gets the carbon by eating the tree's leaves.
Step 3: A bird gets the carbon by eating the caterpillar.
Step 4: The bird flies into a building and dies instantly. It falls to the ground.
Step 5: The bird decomposes and the carbon returns to the atmosphere.