Final answer:
Each initiator caspase can cleave many target proteins, which lead to apoptosis when activated.
Step-by-step explanation:
Each initiator caspase can cleave many target proteins, which when activated lead to apoptosis. Caspases are proteolytic enzymes that digest cellular proteins. For example, caspases can cleave the protein Bid, which triggers the release of cytochrome C and initiates the apoptotic pathway.