Final answer:
The mitochondrion serves an important role in apoptosis by releasing molecules to trigger cell death.
Step-by-step explanation:
The organelle that serves an important role in apoptosis in animals by releasing molecules to trigger cell death is the mitochondrion.
In apoptosis, the mitochondrion releases a protein called cytochrome C into the cytoplasm, which initiates molecular events leading to cell death.
This process is controlled and prevents the release of potentially damaging molecules from inside the cell.