How is the possessive formed if the noun is plural and ends in -s

The literature of nineteenth-century realism depicted everyday life in a realistic way. which statements show that leo tolstoy’s the death of ivan ilyich is a realist text? the description of human struggles in the form of ivan ilyich’s suffering the faithfulness of relationships that ivan ilyich experiences toward the end of his life the romantic tension that occurs between ivan ilyich and his wife the difference between superficial and authentic living the plot ending with a surprising turn of events