Final answer:
Fred's father retains a reversionary interest in the land, as he has granted Fred a life estate.
Step-by-step explanation:
Fred's father retains a reversionary interest in the land. A reversionary interest is a type of future interest where the property owner grants an estate in land to someone else, but retains the right to reclaim ownership of the property once the specified time or condition is met.
In this case, Fred's father has given him a life estate, which means Fred can enjoy the use of the land for the duration of his lifetime. However, once Fred passes away, the ownership of the land will revert back to his father.
It is important to note that a reversionary interest is different from a fee simple estate, which represents absolute ownership of the property, and from pour autre vie, which is a life estate based on the duration of a third party's life.