In a human female, probability of an ovum to get fertilized by more than one sperm…

The probability of an ovum (egg) getting fertilized by more than one sperm is impossible due to a physiological mechanism known as the zona pellucida reaction. After a single sperm penetrates the zona pellucida (the protective layer surrounding the egg), it triggers changes in the zona pellucida that prevent other sperm from binding to and fertilizing the egg. This mechanism ensures that only one sperm successfully fertilizes the egg, preventing polyspermy.