Choose the option that best represents the basis of the 'safe period' method of birth control.
The 'safe period' method is solely determined by the occurrence of ovulation on the 14th day of the menstrual cycle.
The 'safe period' method is based on the ovum's ability to survive for approximately 1 day.
The 'safe period' method relies on sperms having a lifespan of only 2 days.
All of the above options accurately describe the basis for the 'safe period' method of birth control.
The 'safe period' method of birth control takes into consideration multiple factors, including the occurrence of ovulation on the 14th day of the menstrual cycle, the ability of the ovum to survive for approximately 1 day, and the lifespan of sperms, which can be up to 2 days. By avoiding sexual intercourse during the fertile window around ovulation, when both the ovum and sperms are present, the 'safe period' method aims to reduce the chances of pregnancy. Therefore, Option 4 becomes the correct answer.