Below is a list of sets of six letters each. In each case a word can be formed by adding a seventh letter and anagramming. Also in each case, the letter to be added is the last letter in the formed word above it, or, in the case of the first word, its added letter is the last letter in the formed word at the bottom, so as to complete a cyclic set.

Remember, the added letter is the one that ends the completed word that precedes it in a cycle.

D G O P R U

A I Z Z Z Z

E E I R S U

G I N N P U

A C I M R U

---

From Mensa Puzzle Calendar 2021 by Fraser Simpson, Workman Publishing, New York. Puzzle for December 8.