Final answer:
Sperm penetrate the corona radiata using acrosome reaction, flagellar movement, and sperm-egg fusion.
Step-by-step explanation:
To penetrate the corona radiata, sperm use acrosome reaction in which the enzyme-filled acrosome releases its stored digestive enzymes, clearing a path through the zona pellucida. The sperm then travel using flagellar movement to reach the oocyte. Finally, a sperm-egg fusion occurs when a single sperm makes contact with sperm-binding receptors on the oocyte's plasma membrane, resulting in the entry of the sperm into the oocyte.