A more thorough explanation:

The presumption of survivorship is a legal concept that assumes that one person survived another in a common disaster. This presumption is based on certain factors such as age, health, and other reasons that make it more likely for one person to have survived over the others.

For example, if a husband and wife were involved in a car accident and both died, but it is unclear who died first, the presumption of survivorship would come into play. If the husband was younger and healthier than the wife, it would be presumed that he survived her.

Another example would be if a group of people were on a boat that sank, and it is unclear who survived. If one person was a strong swimmer and the others were not, the presumption of survivorship would assume that the strong swimmer survived.

These examples illustrate how the presumption of survivorship is based on certain factors that make it more likely for one person to have survived over the others. It is important in legal matters such as inheritance and insurance claims, where it is necessary to determine who survived in a common disaster.