What property of semen helps protect sperm in the vaginal environment?

The property of semen that helps protect sperm in the vaginal environment is its alkaline fluid. The vaginal environment is naturally acidic, which can be hostile to sperm. The alkaline nature of semen helps neutralize this acidity, creating a safer environment for the sperm to survive and travel through the female reproductive tract. By raising the pH, the alkaline fluid increases the viability of sperm, enhancing the chances of successful fertilization.

This is particularly important as the survival and motility of sperm are significantly impacted by the pH of their surroundings. The balance provided by the alkaline fluid in semen is a crucial factor in the reproductive process.